Spectral response of Silicon Image Sensors

Spectral Response PVEducatio

The spectral sensitivity of silicon is essentially restricted to the spectral wavelength range between 0.1 and 1,100 nm. With a suitable choice of materials that cover the silicon sensor's surface, this sensitive wavelength range can be extended Sensor chip makers publish the spectral response of their devices, usually given as a plot of output level for 1 nJ/cm 2 input vs. wavelength in nanometers. Monochromator readings can be compared to the published levels to verify the sensor response. Finally, we should mention a new kind of image sensor, the Quanta image sensor (QIS) Nanophotonic Image Sensors. Qin Chen. Corresponding Author. qchen2012@sinano.ac.cn. Key Lab of Nanodevices and Applications‐CAS & Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou Institute of Nano‐Tech and Nano‐Bionics, Chinese Academy of Sciences (CAS), Suzhou, 215123 P. R. China Spectral response. as a function of wavelength for the developed CMOS image sensor before and after UV-light μm and the number of pixels is 1280H×960V. Fig. 9 . Sample . images of (a) Rudobekia flower and (b) Shimeji mushroom captured by the developed CMOS image sensor under visible light source and UV-light source (360 nm) INTRODUCTION Hybridized image sensors are actually the only solution for image sensing beyond the spectral response of silicon devices. By hybridization, we can combine the best sensing material.

Optical CMOS sensor system for detection of light sources

  1. g logic, exposure control, analog-to-digital conversion, shuttering, white balance, gain adjustment, and initial image processing algorithms
  2. es the range of frequencies that can be detected with a CCD device. Detection with Silicon CCD devices is possible from 400-900 nm with high quantum efficiency. For UV detection, the CCD devices can be modified to enable imaging. Spectral response of CCD devices
  3. Image Sensor Components. Image Silicon Wafers. Sensor Functions Inside a Camera. Differences Between CCD and CMOS. Mono and Color Sensors. Image Sensor Format (Size) Pixel Size. Spectral Response. Global & Rolling Shutter Type
  4. The Upper Limit of Spectral Response for Silicon Silicon has a bandgap energy of E = 1.12eV From Planck's equation: Wavelength λ = (hc)/E λ = (4.135×10 -15 eV.s x 3×10 8 m/s)/1.12 eV = 1110 n
  5. This manuscript is an extension version of the conference paper: An Ultraviolet Radiation Sensor Using Differential Spectral Response of Silicon Photodiodes. In Proceedings of the IEEE Sensors 2015, Busan, Korea, 1-4 November 2015

Image registration is a fundamental task used in image processing to match two or more images taken at different times, from different sensors or from different viewpoints. The objective is to find in a huge search space of geometric transformations, an acceptable accurate solution in a reasonable time to provide better registered images Our key idea is to approximate the response of the InGaAs sensor by exploiting the largely ignored sen-sitivity of a Silicon sensor, weak as it is, in the SWIR range. To this end, we build a multi-channel optical system to col-lect a new SWIR dataset and present a physically meaning-ful three-stage image processing algorithm on the basis of CNN In order to design and realize multiple wavelength bandpass filters for image sensors, we have investigated optical multi-layer dielectric filters. The filter design is based on a chirped Bragg grating which is approximated by a stack of two alternatively deposited dielectric materials. Multi- layer stacks have been simulated with the rigorous chain- matrix method

Response of a silicon photo diode vs wavelength of the incident light. Critical performance parameters of a photodiode include spectral responsivity, dark current, response time and noise-equivalent power. Early charge-coupled device image sensors suffered from shutter lag The foveon sensor has no filter mosaic, simply 3 junctions at 3 different depths that take advantage of silicon's varying spectral absorption response vs. depth. This conversion process is inherently inefficient, and so Foveon sensors aren't as sensitive as Bayer CFAed CMOS sensors, but they have higher color resolution In this paper, we propose and demonstrate a compact and ultra-sensitive integrated photonic current sensor based on a silicon ring resonator. The proposed sensor possesses the advantages of both silicon photonics and ring resonators. Meanwhile it is suitable for on-chip current sensing. The current flowing through the integrated resistive TiN. The spectral sensitivity of the CCD differs from that of a simple silicon photodiode detector because the CCD surface has channels used for charge transfer that are shielded by polysilicon gate electrodes, thin films of silicon dioxide, and a silicon nitride passivation layer

IMAGE SENSORS: Black silicon sensors target low-light

A combination of ultralow noise image sensor design and our proprietary black silicon NIR enhanced sensing technology enables broad-spectral-response sensors operating from 400 to 1200 nm with approximately 2 e- of read noise within a monolithic CMOS solution. Extended quantum efficiency (trademarked XQE) SiOnyx sensors deliver increased IR. The demonstration of a quantum dot-sensitized graphene image sensor that offers a very broad spectral response and that is integrated with silicon CMOS technology could potentially be a new cost. Spectral sensitivity is the relative efficiency of detection, of light or other signal, as a function of the frequency or wavelength of the signal.. In visual neuroscience, spectral sensitivity is used to describe the different characteristics of the photopigments in the rod cells and cone cells in the retina of the eye.It is known that the rod cells are more suited to scotopic vision and cone. Hybridized image sensors are actually the only solution for image sensing beyond the spectral response of silicon devices. By hybridization, we can combine the best sensing material and photo-detector design with high performance CMOS readout circuitry. In the infrared band, we are facing typically 2 configurations: high background situation and low background situation

Figure 26. Image of downtown Monterey captured with the camera filter (400 nm to 660 nm) affixed. The zoomed-in image of a car is shown.....37 Figure 27. Spectral Response of the FOVEON camera. Each curve represents the response curve of each layer according to its color [12]...38 Figure 28 The spectral response of the 1K Orion sensor with the etalon-free diode, compared with a standard CMOS photodiode. Courtesy of Awaiba. Designed for spectroscopy applications, the Orion family has a configurable read-out chain that allows for a line rate of up to 85 kHz at full resolution over bit-serial low-voltage differential signaling output

spectral response of silicon to the photoptic response of the human eye. Care must be taken with IR radiation if no filter fitted due to diffusion of photon generated charges causing smearing. If a filter is fitted then care must be taken if using a red laser light - for instance at 670 nm, as much of the power of the signal may be attenuated In order to design and realize multiple wavelength bandpass filters for image sensors, we have investigated optical multi-layer dielectric filters. and chirping of the discrete chirped of the discrete chirped Bragg gratings have been optimized to match the blue spectral response. The filter band has been designed to transmit the 400-500nm. the spectral response and frequency response described later can be controlled. When a Si photodiode is illuminated by light and if the light energy is greater than the band gap energy, the valence band electrons are excited to the conduction band, leaving holes in their place in the valence band [Figure 1-2] Image Sensor QE and Spectral Responsivity Characterization Labsphere's Spectra-QT Quantum Tunable Irradiance/Radiance Calibration Source provides control of known levels of uniform monochromatic light over the spectral sensitivity range of silicon-based optical sensors for test and characterization imaging sensors for spectral responsivity and quantum efficiency, linearity, bad pixel and.

The vast majority of image sensors are silicon devices. When photons smash into silicon, the electrons in the silicon are excited and covalent bonds that hold the electrons to the silicon atoms. As expected, the response varies strongly with incident light wavelength. The peak QE occurs between 600 nm and 650 nm. Conclusion The quantum efficiency of a silicon photodiode is proportional to the wavelength of the incident light. The experimental results show that the RadEye image sensor QE peaks at about 40% at 625 nm and decreases rapidl For designers of image sensors striving to make them function as closely to human vision as possible, this curve represents the maximum desirable colour response. How Digital Cameras Capture Colour. The vast majority of electronic cameras sold commercially use a silicon-based image sensor array (either CCD or CMOS) as the image capture device Figure 8 gives sample matrices for X3 and Bayer sensors. Spectral Sensitivity 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 400 450 500 550 600 650 700 Wavelength (nm) Normalized Sensor Response FovR FovG FovB CCDR CCDG CCDB Figure 7: Spectral curves for a Foveon X3 sensor (solid lines) and a typical Bayer CFA (dsahed lines) used in.

CCD and CMOS sensors are sensitive to wavelengths from approximately 350 - 1050nm, although the range is usually given from 400 - 1000nm. This sensitivity is indicated by the sensor's spectral response curve (Figure 8). Most high-quality cameras provide an infrared (IR) cut-off filter for imaging specifically in the visible spectrum. These. Spectral response of multispectral filter array (a) Top: photograph of multispectral filter mounted on 1/4 inch monochrome charge-coupled device (CCD) image sensor or p+/n- junction is often applied to CMOS imag e sensors [15], [23]-[26]. Since the spectral response of silicon covers visible light and infrared regions, n-/p-sub and p+/n-/p-sub photodiodes can be used in commercial CMOS image sensors. Owing to the junction between n- and p-substrate deeper than that between p+ and n-, the n-/p-sub junction i

front sensor (WFS150-7AR, Thorlabs) [Fig. 1(a)] that consists of a silicon CCD camera (1280× 1024 pixels, pixel size of 4.65 μm) and a 39× 31 MLA with an effective focal length of 5.2 mm and microlens pitch of 150 μm. The linear spectral response of the silicon-based camera is limited by the response of silicon as shown in Fig. 2 A spectral signature plots all the variations of reflected EM radiation as a function of wavelengths. Pick and choose the spectral bands you use in your classification. If you want to pull out vegetation from a multispectral image, this spectral signature clearly shows you should leverage the near-infrared band (0.76-0.9µm)

A CMOS image sensor is a typical solid-state imaging sensor and has a common historical origin with CCD. CMOS image sensors are usually composed of image sensor cell array, row driver, column driver, timing control logic, AD converter, data bus output interface, control interface, etc. These parts are usually integrated on the same silicon chip Commonplace, low-cost imagers with silicon CCD and CMOS sensors can be used to image in the NIR band up to about 1.1 µm in wavelength. These silicon detectors usually have their peak sensitivity around 800 nm and also see visible light, which may need to be filtered out, depending on the application The sensors have good omnidirectionality; the difference in sensor response is below 25% for the ultrasound angle of incidence measured up to 60° (Supplementary Section 9)

Silicon Sensor - an overview ScienceDirect Topic

• Broad spectral response • Sensitive from 400 nm to 1700 nm • Room temperature operation • Low noise • Non-ITAR (EAR 99 Classification) • Global shutter • XVGA format (1280x1024 pixels) - available in spring 2017 www.rti.org Images generated by a RTI-CQD SWIR image sensor with a 640 x 512 format array with 15 μm pixel pitch Here, a few different characterization techniques will be outlined, including color accuracy and Bayer filter spectral mismatch, image-sensor linearity, and frame rate/readout time. The fundamental limits of halogen sources for characterizing silicon charge-coupled device (CCD) and complementary metal-oxide semiconductor (CMOS) sensors will. To mimic the mantis shrimp's multispectral capabilities, we designed and fabricated an image sensor by monolithically integrating an array of vertically stacked silicon photodetectors with an array of pixelated spectral filters (Fig. 1, C and D).The absorption length of silicon strongly varies with wavelength, with 99% of blue photons (~400 nm) absorbed within 0.5 μm of penetration and 99%. Silicon based CCD and CMOS sensors are used where possible for NIR applications due to their lower cost compared with other sensor materials. As silicon based sensors only show a limited efficiency in converting photons into electrons in the wavelength >1000 nm, manufacturers try to use special circuits or sensor coatings to get the remaining. An innovative pixel array system formed by new structures and design mechanisms of silicon, SeeDevice's proprietary image sensor uses Quantum Tunneling resulting in high sensitivity, quantum efficiency, low SNR, and wide spectral response

How to measure CCD and CMOS image sensor qualitie

The red channel has a spectral response from 580 nm to 750 nm, which is maximum at around 620 nm with a quantum efficiency of 31%. Both CFA and stacked photodetector type spectral sensors require further image processing in order to map the spectral response on to, for example, sRGB or CIEXYZ color space for accurate color reproduction An improved monolithic solid state imager comprises plural sub-arrays of respectively different kinds of pixels, an optional filter mosaic comprising color filters and clear elements, and circuitry to process the output of the pixels. The different kinds of pixels respond to respectively different spectral ranges. Advantageously the different kinds of pixels can be chosen from: 1) SWIR pixels. detector. The silicon detector array developed operates in a back-illuminated mode. When combined with a fully depleted device design, the spectral response can cover a broad wavelength band ranging from UV to NIR. At UV wavelengths (≤400nm) where the incident photons are absorbed very close to the silicon surface, the surface design an Conventionally, silicon photodiode UV light sensors employ optical filters that cut off undesired visible light wavebands. By utilizing the differential spectral response of silicon photodiodes with high and low UV light sensitivities, the researchers were able to develop a sensor with UV range selective sensing capabilities without employing. Tungsten lights emit very little blue (short wavelengths), and a whole lot of yellow / red / IR (long wavelengths), so if you combine the emission spectrum of Tungsten lights with the spectral response of Silicon, then you have a lot of 'signal' in the yellow / red region and very little signal in the blue region, and on a colour camera you are.

The results of our efforts are summarized in Figure 2. Figure 2 shows the quantum efficiency of standard InGaAs in blue together with the quantum efficiencies of two extended wavelength alloys, X=0.74 (green) and X=0.82 (red). The spectral response of silicon is also shown. As we like to say, InxGa1-xAs starts where silicon leaves off sensor, (b) transmission spectra showing the temperature-dependent resonance wavelength shift, and (c) spectral response of the fabricated SOI ring resonator [48]... 7 Figure 1.4 (a) Noise power spectral density as a function of sampling time scale an the spectral transmittance of colour filters and optics between the lens and the detector. For example, colour information is usually obtained in a consumer digital camera by covering the image sensor with a patterned array of red, green and blue colour filters in front of the detectors Silicon carbide SiC photodetectors / photodiodes have a spectral response of approximately 210 - 380 nm and are not sensitive to UV radiation outside this region. This makes them ideal detectors in certain applications for monitoring the UV spectrum without the need for solar rejection filters In this paper, a new visible image sensor with 110 dB intrascene dynamic range is reported. The sensor captures four linear response images with different sensitivities simultaneously at 60 frames per second (fps). A real time fusion and dynamic range compression (DRC) algorithm, which is implemented by an FPGA, is also presented

Deep red rendering on CMOS and CCD - Page 2 - PentaxForums

US9786705B2 US15/057,818 US201615057818A US9786705B2 US 9786705 B2 US9786705 B2 US 9786705B2 US 201615057818 A US201615057818 A US 201615057818A US 9786705 B2 US9786705 B2 US 978 Accuracy depends upon the sensitivity of the material used in the sensors, the response time, and the distortion characteristics of the material constituting the dome (if present) covering the sensors. For silicon photocell pyranometers, electric current is generated by a photo-sensitive diode in proportion to solar intensity The camera features EIA output, which is used extensively in the industry. When compared to Hamamatsu's traditional model, the spectral response at 900 nm is improved more than twice. Thanks to its high sensitivity in the NIR region, the C3077-80 CCD camera is ideal for imaging inside a silicon device. Download the Brochure for More Informatio IMAGE CAPTURE: Black silicon sensors promise increased sensitivity. USA;www.harvard.edu) is promising to increase dramatically both the spectral response and responsivity of CMOS-based imagers. Discovered as a fortuitous accident in the laboratories of Eric Mazur at Harvard, black silicon sensors were born as the result of studying the.

Although this sensor is intended for use in color imaging, its response extends over the usual band of wavelengths detectable by silicon imaging devices †from about 340 nm to nearly 1100 nm. The three photodiodes in each pixel stack are accurately aligned, so that their output signals may be added together without generating. Kuroda R., Kawada S., Nasuno S., Nakazawa T., Koda Y., Hanzawa K., Sugawa S. A FSI CMOS Image Sensor with 200-1000 nm Spectral Response and High Robustness to Ultraviolet Light Exposure; Proceedings of the International Image Sensor Workshop 2013; Snowbird, UT, USA. 12-16 June 2013; pp. 61-64. [Google Scholar By utilizing the differential spectral response of silicon photodiodes with high and low UV light sensitivities, the researchers were able to develop a sensor with UV range selective sensing. Abstract: An ultraviolet (UV) sensor is demonstrated with high sensitivity in the UV waveband and low sensitivity in the visible (VIS) and near-infrared (NIR) wavebands, utilizing only bulk silicon technology. The developed sensor utilizes the differential spectral response of photodiodes (PDs) with a high UV sensitivity (PD1) and a low UV sensitivity (PD2), for UV signal extraction under a. In this paper, two new photodiode structures using p-substrate and lightly-doped sensor implant SN- as pn-junction photodiode with the regions of bird's beak embraced by SN- and p-field implants, respectively, are proposed and analyzed to reduce dark current and enhance the overall spectral response. 5 μm × 5 μm APS cells fabricated in a 0.

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Nanophotonic Image Sensors - Chen - 2016 - Small - Wiley

process, which means that the same image processing and calibration used for linear detection can be used in 2P-SHWS without any need for special adjustments. Figure 2. (a) Spectral response of the silicon-based detector (blue) and InGaAs detector (red), referred source: Thorlabs. Measure Adaptive solid state image sensor . United States Patent Application 20060055800 . Kind Code: A1 . Abstract: An improved monolithic solid state imager comprises plural sub-arrays of respectively different kinds of pixels, an optional filter mosaic comprising color filters and clear elements, and circuitry to process the output of the pixels. Hyperspectral imaging camera demo-kits including imec HSI sensor (s), camera housing, lens, tripod mounts, reflectance calibration tile, lighting solution, storage box and imec HSImager™ hyperspectral imaging software license are available from imec directly to ease your application work. Explore all cameras An ultraviolet (UV) sensor is demonstrated with high sensitivity in the UV waveband and low sensitivity in the visible (VIS) and near-infrared (NIR) wavebands, utilizing only bulk silicon technology. The developed sensor utilizes the differential spectral response of photodiodes (PDs) with a high UV sensitivity (PD1) and a low UV sensitivity.

Hamamatsu Introduces An Ultra-Small MEMS-FPI Spectrum Sensor

responses of the eye are shown in Figure 64.1 with the response of a typical silicon-based sensor for comparison . The lat ter has a spectral response that is quite diffe rent f rom that of the human e ye, extending well beyond the red end of the visible spectrum toward 1100 nm, with maximum sensitivity around 800 nm n of air or vacuum is 1.0, glass is 1.46, water is 1.33, Silicon is 3.6. Using the above equation we can show that window glass in air reflects 3.5% and silicon in air reflects 32%. Unless we take steps to eliminate this reflected portion, then a silicon CCD will at best only detect 2 out of every 3 photons Right: Spectral response of the Toshiba TCD1304AP/DG CCD sensor (adapted from manufacturer datasheet). A silicon substrate is used for visible imaging detectors. Although silicon is well characterized, the actual form of the QE curve is different for every detector and a rough indication is typically provided in the manufacturer's datasheet Their very high spectral resolution facilitates fine discrimination between different targets based on their spectral response in each of the narrow bands. Whiz quiz. 1. Hyperspectral scanners (mentioned in Chapter 2.4) are special multispectral sensors which detect and record radiation in several (perhaps hundreds) of very narrow spectral bands The technology of thinning and back-illumination is now well established for CCD image sensors. By avoiding losses in the electrode structure, a high quantum efficiency can be obtained right across the useful spectral range of silicon from X-ray to near infra-red wavelengths

(Pdf) Low Noise Wdr Roic for Ingaas Swir Image Senso

Spectral Cover of Landsat Sensors Hyperspectral Data Example: Hyperion hyperspectral sensor is capable of resolving 220 spectral bands at 10 nm interval (from 0.4 to 2.5 µm) with a 30 meter spatial resolution. The shown image, acquired April 6, 2004, is displayed as--640.50 µm in Red color--548.92 µm in Green color--457.34 µm in Blue colo Perovskite quantum dots embedded composite film (PQDCF) exhibits strong photoluminescence emissions and is expected to be excellent down-shifting material for enhancing ultraviolet (UV) response of silicon devices. In this work, light conversion process is analyzed by combining the experiments with Monte-Carlo ray-trace simulation. Results show that external quantum efficiency (EQE) in the UV. • We have been developing and manufacturing CMOS image sensors since 2006. Our technology portfolio, based on 200 mm wafers, includes different process nodes down to 90 nm (minimum feature for transistor gate length)

Introduction to CMOS Image Sensors - Florida State Universit

Silicon sensors are sensitive throughout the visible to wavelengths as long as the silicon bandgap of ~1.1 μm. Just the opposite of the UV situation discussed above, the very long absorption length associated with the indirect bandgap of silicon requires very different optimization of the device structure for quantum efficiency and carrier. system. Spectral response up to 2.7 microns is also desired. Detector and Optics Design. Optical sensing in the visible and infrared regions of the spectrum presently requires the use of two types of detectors. Silicon (Si) photodiodes provide spectral detectivity in the visible region and lead sulfide (PbS) photoconductive sensors the characteristics of sensor's spectral response, thus this kind of images obtained by different sen- sots' data can be used to analyze the differences of the sensors' spectral response features. Atmospheric effect to remote sensing imaging is very complicated. Generally, the model methods ar

The organic dye filters of conventional color image sensors achieve the red/green/blue response needed for color imaging, but have disadvantages related to durability, low absorption coefficient, and fabrication complexity. Here, we report a new paradigm for color imaging based on all-silicon nanowire devices and no filters. We fabricate pixels consisting of vertical silicon nanowires with. Spectral response range 800-900 nm; Suitable for LED or laser illumination; This new device is a CIS detector whereas the existing market uses a silicon TFT type sensor. The advantage of CIS compared to TFT is that CIS uses active pixels so it obtains the image with less noise and helps minimize X-ray radiation exposure which is currently. Fig.7 Spectral Sensitivity Characteristic of InGaAs Photodiode 3) Indium gallium arsenide (InGaAs) is a compound semiconductor. Like a silicon photodiode, an InGaAs photodiode is a photovoltaic element that has a P-N junction. The band gap energy of InGaAs, however, is smaller than that of silicon, so it absorbs light of longer wavelengths Lisa SWIR - The Ultimate Tool for Electronic Components, Silicon Wafers, and Solar Panels Inspection. Jun 22, 2021. The SenS 1280V-ST HD SWIR camera is ready for sale. May 17, 2021. May 4, 2021. NIT starts production of its SWIR SXGA image sensor. Apr 22, 2021. Terms & Conditions. Legal statements General Terms & Conditions of Sale

Charge Coupled Devices and CMOS Sensors for Superior Imagin

Convolve: While the full process of convolve is to simulate how a satellite sensor detects a surface feature in each spectral band, in this current viewer version, the Convolve function displays only the full width at half maximum values (FWHM) for the selected satellite bands; full convolve functionality will be included in a future update of. Silicon photodiodes are the most common detectors of light used in instrumentation. The spectral response covers the UV, the visible and the near infrared. The linearity and dynamic range are excellent; getting a signal is simple. Figure 9 shows the typical structure of a silicon photodiode

Virginia TWP's SloMo: High-speed cameras - CCD/CMOS sensor and lens info

It is where serious imaging people come to meet. LG Electronics. Image Sensors & IS Auto Online 2020 is brought together experts from the auto industry and companies from all areas of the image sensor supply chain to support advancements in the imaging industry and improve the quality of products we use in our everyday lives.This event united globally recognized experts for high caliber. Abstract: An ultraviolet (UV) sensor is demonstrated with high sensitivity in the UV waveband and low sensitivity in the visible (VIS) and near-infrared (NIR) wavebands, utilizing only bulk silicon technology. The developed sensor utilizes the differential spectral response of photodiodes (PDs) with a high UV sensitivity (PD1) and a low UV sensitivity (PD2), for UV signal extraction under a. nominal response wavelength band (from 8 to 14 microns) and outputs a uniform thermal image. Features Dimensions: 8.5 x 11.7 x 5.6 mm (without socket), 10.6 x 11.7 x 5.9 mm (including socket) 51-deg HFOV, 63.5-deg diagonal (f/1.1 silicon doublet) LWIR sensor, wavelength 8 to 14 μm 80 (h) × 60 (v) active pixels Thermal sensitivity <50 m Spectral response estimate of Apogee silicon-cell pyranometers. Spectral response was estimated by multiplying the spectral response of the photodiode, diffuser, and adhesive. Spectral response measurements of diffuser and adhesive were made with a spectrometer, and spectral response data for the photodiode were obtained from the manufacturer

All About Sensors--Optical and Radiation SensorsCan we compare the color reproduction accuracy of 2 cameraPyranometer - Manufacturers, Suppliers & WholesalersInGaAs Avalanche Photodiodes

Spectral ResponseIt is important to include sensor spectral response information in image fusion methods for the following reasons.-In order to preserve physical meaning of merged spectral bands, the sensor spectral response for each band has to be taken into account. It is not physically acceptable to include, for example, information from far. The cheapest sensor types by far are CCD and CMOS. They work by taking advantage of the bandgap phenomena of silicon. A sensor is optimized if it's tuned for a wavelength more powerful than the bandgap, but not too powerful. The badgap for silicon corresponds to a 1.1 um light Vescoli mentioned a spectrometric device example based on single-slit folded grating-based optics. This is consisting of a silicon sensor, but the spectral range is covered by a pure wafer-level optics (WLO) construction. The above slide shows the spectral footprint of a stressed plant in the wavelength range of 300 to 1000 nm Various filter windows are also available to tailor the spectral response to suit the application. One specific filter which is of great interest, modifies the normal silicon response to approximate the spectral response of the human eye. Linearity The output of photodiode when reverse-biased is extremely linear with respect to the illuminance. CCD image sensors are fabricated with materials (e.g. silicon dioxide, polysilicon, nitrides, etc.) overlying the silicon. These materials are added to keep unwanted impurities out of the silicon or, in the case of frame transfer or full−frame transfer architectures, are necessary for reading the collected charge out of the device. Ideally, on Image sensors typically employed in fluorescence microscopy can detect photons within the spectral range of 400-1100 nanometers, with peak sensitivity normally in the range of 550-800 nanometers. Maximum QE values are only about 40-50 percent, except in the newest designs, which may reach 80 percent efficiency