Method of Calculating the MTF and SNR for Low-Light Detectors

Fig. 1. EMCCD low-light detector. (a) Structure schematic diagram of EMCCD low-light detector; (b) electrode-potential distribution of EMCCD low-light detector

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Fig. 2. 3D distribution of MTF for EMCCD low-light detector. (a) Detector MTF; (b) three-phase transfer MTF; (c) transfer efficiency MTF; (d) total MTF

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Fig. 3. Specific realization form of MCP detector system

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Fig. 4. 3D distribution of MTF for MCP low-light detector system. (a) MCP MTF; (b) back proximity MTF; (c) front proximity MTF; (d) fiber optic taper MTF; (e) detector MTF; (f) total MTF

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Fig. 5. 2D distribution of pixel MTF for square photosensitive aperture

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Fig. 6. Pixel structure of backside illumination sCMOS image sensor

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Fig. 7. 2D spatial distribution of MTF for sCMOS image sensor

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Fig. 8. Variation in SNR for three types of low-light detectors. (a) Different numbers of incident photon at the same integration time; (b) different integration time at the same number of incident photon

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Fig. 9. 2D distribution of MTF for three types of low-light detectors

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Table 1. Functions and parameters of MTF for EMCCD low-light detector

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Table 1. Functions and parameters of MTF for EMCCD low-light detector

MTF component	Function	Parameter
Detector MTF	$M_{M T F, C C D} = \frac{s i n (π ω f)}{π ω f}$	$ω$ is CCD pixel size， $f$ is spatial frequency
Three-phase transfer MTF	$M_{M T F, p h a s e} = \frac{s i n (π ω f / 2 N)}{π ω f / 2 N}$	N is EMCCD phase
Transfer efficiency MTF	$M_{M T F, t r a n s f e r} = e x p [- \frac{2 (1 - η)}{N'} f^{2}]$	η is EMCCD transfer efficiency， $N'$ is EMCCD transfer stages

Table 2. Functions and parameters of MTF for ICCD/ICMOS low-light detector

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Table 2. Functions and parameters of MTF for ICCD/ICMOS low-light detector

MTF component	Function	Parameter
Front proximity MTF	$M_{M T F, b a c k} = e x p [- \frac{8}{33} π^{2} L_{1}^{2} \frac{ε_{m 1}}{ϕ_{1}} f^{2}]$	$L_{1}^{}$ is front proximity distance， $ϕ_{1}$ is acceleration voltage of front proximity， $ε_{m 1}$ is photocathode max initial voltage of front proximity
MCP MTF	$M_{M T F, M C P} = \|\frac{J_{1} (2 π f d_{c})}{π f d_{c}}\|$	$d_{c}$ is MCP single filament diameter， J₁ is first order Bessel function
Back proximity MTF	$M_{M T F, b a c k} = e x p [- \frac{1}{9} π^{2} L_{2}^{2} \frac{ε_{m 2}}{ϕ_{2}} f^{2}]$	$L_{2}^{}$ is back proximity distance， $ϕ_{2}$ is acceleration voltage of back proximity， $ε_{m 2}$ is photocathode max initial voltage of back proximity
Fiber optic taper MTF	$M_{M T F, f o p} = \|\frac{J_{1} (2 π f d)}{π f d}\|$	d is fiber optic single filament diameter
Detector MTF	$M_{M T F, C C D} = \frac{s i n (π ω' f)}{π ω' f}$	$ω'$ is CCD/CMOS pixel size

Table 3. Parameters of sCMOS and qCMOS image sensors

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Table 3. Parameters of sCMOS and qCMOS image sensors

Parameter	Hamamatsu GenIII	GSENSE1516 sCMOS	GLUX9701 sCMOS	Gigajot Quanta CMOS image sensor	ORCA-Quest qCMOS
Pixel size /（μm×μm）	6.5×6.5	15×15	9.76×9.76	1.1×1.1	4.6×4.6
Pixel number （H×V）	2304×2304	4096×4096	1280×1024	4096×4096	4096×2304
Full well capacity /ke^-	15	134	50	2	7
Read noise /e^-	0.7	4	0.8	0.19	0.27
Dark current /（e^-·pixel^-1·s^-1）	<0.7@-15 ℃	0.04@-50 ℃	—	0.09@25 ℃	0.006@-35 ℃
Peak quantum efficiency /%	95	95@580 nm	95	76@520 nm	90@475 nm

Table 4. Parameters for three types of low-light detectors

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Table 4. Parameters for three types of low-light detectors

Parameter	EMCCD	MCP	sCMOS
Product model	Andor EMCCD	iStar ICCD	GSENSE1516 sCMOS
Pixel size /μm	13.3	13	15
Nyquist frequency /（lp·mm^-1）	37.6	38.5	33.3
Total MTF@Nyquist frequency	0.48	0.13	0.63
^1）Number of input photon@SNR=1	2.25	4.27	1.92
^2） SNR	6.89	3.53	9.67
Image quality （MTF×SNR）	3.31	0.46	6.09

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Gengyun Wang, Bu Hongbo, Weijun Pan. Method of Calculating the MTF and SNR for Low-Light Detectors[J]. Laser & Optoelectronics Progress, 2025, 62(9): 0904001

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Paper Information

Category: Detectors

Received: Aug. 30, 2024

Accepted: Nov. 5, 2024

Published Online: Apr. 15, 2025

The Author Email: Gengyun Wang (wanggy16@126.com)

DOI:10.3788/LOP241930

CSTR:32186.14.LOP241930

Topics

laser devices and laser physics

Lasers and Laser Optics

Laser physics

laser manufacturing

Instrumentation, Measurement and Metrology