Parametric upconversion imaging and its applications

Ajanta Barh; Peter John Rodrigo; Lichun Meng; Christian Pedersen; Peter Tidemand-Lichtenberg

doi:10.1364/AOP.11.000952

Advances in Optics and Photonics
Vol. 11,
Issue 4,
pp. 952-1019
(2019)
•https://doi.org/10.1364/AOP.11.000952

Parametric upconversion imaging and its applications

Ajanta Barh, Peter John Rodrigo, Lichun Meng, Christian Pedersen, and Peter Tidemand-Lichtenberg

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Ajanta Barh, Peter John Rodrigo, Lichun Meng, Christian Pedersen, and Peter Tidemand-Lichtenberg, "Parametric upconversion imaging and its applications," Adv. Opt. Photon. 11, 952-1019 (2019)

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- Instrumentation, Measurement, and Optical Sensors
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About this Article
History
- Original Manuscript: February 6, 2019
- Revised Manuscript: October 31, 2019
- Manuscript Accepted: November 1, 2019
- Published: December 18, 2019

Abstract

This paper provides an extensive survey of nonlinear parametric upconversion infrared (IR) imaging, from its origin to date. Upconversion imaging is a successful innovative technique for IR imaging in terms of sensitivity, speed, and noise performance. In this approach, the IR image is frequency upconverted to form a visible/near-IR image through parametric three-wave mixing followed by detection using a silicon-based detector or camera. In 1968, Midwinter first demonstrated upconversion imaging from short-wave-IR (1.6 μm) to visible (484 nm) wavelength using a bulk lithium niobate crystal. This technique quickly gained interest, and several other groups demonstrated upconversion imaging further into the mid- and far-IR with significantly improved quantum efficiency. Although a few excellent reviews on upconversion imaging were published in the early 1970s, the rapid progress in recent years merits an updated comprehensive review. The topic includes linear imaging, nonlinear optics, and laser science and has shown diverse applications. The scope of this article is to provide in-depth knowledge of upconversion imaging theory. An overview of different phase matching conditions for the parametric process and the sensitivity of the upconversion detection system are discussed. Furthermore, different design considerations and optimization schemes are outlined for application-specific upconversion imaging. The article comprises a historical perspective of the technique, its most recent technological advances, specific outstanding issues, and some cutting-edge applications of upconversion in IR imaging.

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Parameter	System-I	System-II
FoV	Phase matching condition, $\sim {sinc}^{2} (\frac{Δ k_{z} l_{c}}{2})$	Pump diameter ( $2 w_{0}$ ) and/or crystal aperture size, whichever is smaller
Resolution	Size of resolvable element in the image plane, $d_{res} = \frac{\sqrt{2 \ln (2)} λ_{up} f_{2}}{π w_{0}}$	Size of resolvable element in the image plane, $d_{res} \approx \frac{2 \ln (2) λ_{up} z_{4}}{π \| ψ_{up, acc .}^{FWHM} \| z_{3}}$
Magnification	$M = - \frac{f_{2} \cdot λ_{up}}{f_{1} \cdot λ_{IR}}$	$M = \frac{z_{2} \cdot z_{4}}{z_{1} \cdot z_{3}}$ , $z_{1, 2} > f_{1}$ and $z_{3, 4} > f_{2}$
Efficiency	For Gaussian pump and within the FoV, the efficiency decreases for higher spatial frequencies.	For Gaussian pump and within the FoV, the efficiency decreases for off-axis object points.

Crystal	Nonlinear Coefficient (pm/V)	Refractive Index ( $n$ )	Transmission Window (μm)	LDT ( $MW / {cm}^{2}$ )	Pump Wavelength to Avoid TPA	Birefringence ( $Δ n = n_{e} - n_{o}$ )	$d n / d T \times 10^{5}$ ( $K^{- 1}$ )	Thermal Cond. (W/m-K)	Reference
Proustite ${Ag}_{3} {AsS}_{3}$ uniaxial	d22 (18), d31 (11.3)	$n_{e}$ (2.59), $n_{o}$ (2.82) at 1 μm	0.6–13	4 (ns) at 1.06 μm	$λ_{p} > 0.6 μm$	−0.2	–	–	[20,22,56,129]
${KH}_{2} {PO}_{4}$ (KDP) uniaxial	d36 (0.43)	$n_{e}$ (1.46), $n_{o}$ (1.49) at 1.06 μm	0.18–1.5	$10^{4}$ (ns)	$λ_{p} > 0.3 μm$	−0.03	−3.94 ( $o$ ) −2.54 ( $e$ ) at 0.6 μm	1.9	[60,24,130,99]
${LiB}_{3} O_{5}$ (LBO) biaxial	d31 (1.05) d32 (−1.0) d33 (0.05)	$n_{X}$ (1.57), $n_{Y}$ (1.59), $n_{Z}$ (1.61) at 1 μm	0.16–2.6	$> 10^{4}$ (10 ns) at 1.064 μm	$λ_{p} > 0.35 μm$	–	−0.93 ( $x$ ) −1.36 ( $y$ ) −0.63 ( $z$ )	3.5	[131–133]
$β - {BaB}_{2} O_{4}$ (BBO) uniaxial	d22 (2.3), d31 (0.16)	$n_{e}$ (1.54), $n_{o}$ (1.66) @ 1 μm	0.2–3.5	$1.35 \times 10^{4}$ (ns) at 1.06 μm	$λ_{p} > 0.4 μm$	−0.11	−1.66 ( $o$ ) −0.93 ( $e$ )	1.6 ( $‖ c$ ) 1.2 ( $⊥ c$ )	[99,134–137]
${KNbO}_{3}$ biaxial	d32 (20.4) at 1 μm	$n_{X}$ (2.26), $n_{Y}$ (2.22), $n_{Z}$ (2.12) at 1 μm	0.4–4.5	$\sim 2 \times 10^{4}$ (0.7 ns) at 1.054 μm	$λ_{p} > 0.3 μm$	–	2.2 ( $‖ a$ ) 6.5 ( $‖ c$ )	4	[72,99]
${KTiOPO}_{4}$ (KTP) biaxial	d31 (6.5) d33 (13.7)	$n_{X}$ (1.74) $n_{Y}$ (1.748) $n_{Z}$ (1.83) at 1.064 μm	0.35–4.5	$15 \times 10^{3}$ (1 ns) at 1.064 μm	$λ_{p} > 0.45 μm$	–	1.1 ( $x$ ) 1.3 ( $y$ ) 1.6 ( $z$ )	13	[70,133,138,139]
${LiNbO}_{3}$ uniaxial	d32 (−30), d31 (−5.9)	$n_{e}$ (2.16), $n_{o}$ (2.23) at 1.064 μm	0.4–5.5	$10^{3}$ (ns) at 1.05 μm	$λ_{p} > 0.5 μm$	−0.08	−0.09 ( $o$ ) $+ 3.91$ ( $e$ ) at 1.4 μm	$\sim 5$	[19,140,130]
${ZnGeP}_{2}$	d36 (79) at 4.56 μm	$n_{e}$ (3.3), $n_{o}$ (3.25) at 1 μm	1–12	100 (10 ns) at 2.09 μm	$λ_{p} > 1.5 μm$	0.05	21.18 ( $o$ ) 23.01 ( $e$ ) at 1 μm	36 ( $‖ c$ ) 35 ( $⊥ c$ )	[31,121,130]
${AgGaS}_{2}$ uniaxial	d36 (12.6) at 10.6 μm	$n_{e}$ (2.4), $n_{o}$ (2.45) at 1.06 μm	0.47–13	150 (5 ns) at 1.064 μm	$λ_{p} > 0.8 μm$	−0.05	16.7 ( $o$ ) 17.6 ( $e$ ) at 1.06 μm	1.4 ( $‖ c$ ) 1.5 ( $⊥ c$ )	[121,124,130]
${AgGaSe}_{2}$ uniaxial	d36 (33) at 10.6 μm	$n_{e}$ (2.68), $n_{o}$ (2.70) 1.06 μm	0.76–18	$\sim 25$ (10 ns) at 1.06 μm	$λ_{p} > 1.9 μm$	−0.02	9.8 ( $o$ ) 6.6 ( $e$ ) at 1.06 μm	1.0 ( $‖ c$ ) 1.1 ( $⊥ c$ )	[121,141]
${LiInS}_{2} / {LiInSe}_{2}$ biaxial	d31 (7.3/11.8) d24 (5.7/8.2) at 2.3 μm	$n_{X}$ (2.171) $n_{Y}$ (2.212) $n_{Z}$ (2.22) at 0.7 μm	0.35–13	$\sim 10^{3}$ (10 ns) at 1.064 μm	$λ_{p} > 0.8 μm$	–	5.68 ( $x$ ) 9.34 ( $y$ ) 7.37 ( $z$ )	6.2 ( $x$ ) 6.0 ( $y$ ) 7.6 ( $z$ )	[127,142,143]
${BaGa}_{4} {Se}_{7}$ biaxial	d11 (18.2) d13 (20.6)1.064 μm	$n_{X}$ (2.486) $n_{Y}$ (2.502) $n_{Z}$ (2.559) at 1 μm	0.78–15	557 (5 ns) at 1.064 μm	$λ_{p} > 0.9 μm$	0.07 (max) at 1.06 μm	5.39 ( $x$ ) 5.56 ( $y$ ) 5.23 ( $z$ ) 1.53 μm	0.74 ( $x$ ) 0.64 ( $y$ ) 0.56 ( $z$ )	[144–146]
${BaGa}_{2} {GeSe}_{6}$ uniaxial	d11 ( $49 \pm 15$ )	$n_{e}$ (2.63), $n_{o}$ (2.52) at 1 μm	0.6–12	110 (100 ns) at 10.6 μm	$λ_{p} > 1.08 μm$	0.08–0.11	–	–	[126,147]
OPGAP	d14 (70.6)	$n$ (3.04) at 2 μm	0.7–12.5	$\sim 56$ (15 ns) at 1.064 μm	$λ_{p} > 0.9 μm$	–	–	$\sim 110$	[79], [148]
OpGaAs	d14 ( $\geq 90$ )	$n$ (3.3) at 4 μm	0.85–18	$\sim 2 \times 10^{5}$ (35 ps, 10 Hz) at 1.064 μm	$λ_{p} \geq 2 μm$	–	$\sim 14.7$ at 10 μm	$\sim 55$	[149–151]

Spatial
Temporal	Coherent	Incoherent
Coherent	Laser (DPSS)	Random laser, laser illuminated diffuser
Incoherent	LED with pinhole, supercontinuum from single mode optical fiber, fiber-coupled amplified spontaneous emission (ASE) source	Incandescent light bulb, extended blackbody radiation, sunlight

Aperture	Circular ( $diameter = D_{circle}$ )	Square ( $width = D_{width}$ )	Gaussian ( $diameter = D_{FWHM}$ , $D_{1 / e}$ , $D_{1 / e^{2}}$ )
PSF (Intensity profile)	Airy pattern	${sinc}^{2}$ function	Gaussian
Angular Resolution	$\frac{1.22 λ}{D_{circle}}$	$\frac{λ}{D_{width}}$	$1 / e^{2}$ match point	FWHM match point	$1 / e$ match point
Angular Resolution			$\frac{4 λ}{π D_{1 / e^{2}}}$	$\sqrt{\frac{\ln (2)}{2}} \frac{4 λ}{π D_{FWHM}}$	$\sqrt{\ln (2)} \frac{4 λ}{π D_{1 / e}}$

Year [Ref.]	Crystal (Length), Phase Matching (PM)	Pump (nm)	IR Spectral Range (μm)	Quantum Efficiency	FoV (deg. Unless Otherwise Specified)	Spatial Resolution (Object)	Up-Noise
1968 [183]	KDP, both coherent and incoherent upconversion	Nd-YAG (1064), CW, 0.3 W	He–Ne laser (1.15), Hg-lamp (1–1.5)	–	–	70 lines/inch	$4 \pm 2$ counts/s/raster point
1968 [19]	${LiNbO}_{3}$ (1 cm), temperature tuning	ruby (694), Pulse	1.6	$\sim 10^{- 7}$	3.44	50 total lines	–
1968 [28]	${LiNbO}_{3}$ (1 cm), non-collinear CPM (theory)	ruby (694), Pulse	5.2	$\sim 10^{- 4}$	–	500 total lines	2500 counts/s/pixel
1968 [20]	Proustite (1.2 cm), angular PM	ruby (694), Pulse	10.6	$\sim 10^{- 6}$	17.2	$N_{res} = 20$	–
1969 [22]	Proustite (0.45 cm), tangential PM	ruby (694), Pulse	10.6	–	17.2	–	–
1969 [23]	KDP (1 cm) NCPM, rotation of crystal	ruby (694), Pulse	1.06	–	20	–	–
1970 [24]	KDP (0.3 cm)	$Q$ -switched, Nd-laser (1064)	1.06	$\sim 10^{- 3}$	–	18 lines/mm	–
1971 [31]	${ZnGeP}_{2}$ (1 cm), 90° NCPM	Nd-YAG (1064)	10.6	0.014	3.6	–	Thermal background $noise power = 13 pW$
1972 [25]	Proustite (1 cm), angular PM	ruby (694.3) Non- $Q$ -switched	10, bandwidth 500 nm	$6 \times 10^{- 6}$	30	1.2 cm/cycle	Up-noise $\sim 50 μW$ at 300 K
1972 [198]	KDP (0.27 cm), critical non-collinear	ruby (694), pulse	1.06 (pulse)	$5 \times 10^{- 3}$	49	$Angularres . = 0.017 °$ , $N_{res} = 10^{6}$	–
1972 [152]	Proustite (single crystal), angular PM	Nd-YAG (1064), CW	10.6	–	12	3.56 lines/mm ( $> 40$ lines within FoV)	–
1975 [120]	Proustite, angular PM with cylindrical focusing of pump	Nd-YAG (1064), quasi CW	10	–	–	$N_{res} = 42$	–
1976 [59]	${LiNbO}_{3}$ (5 cm), collinear 90° PM, temperature tuning	Argon-laser (514.5), CW, 1 W	2.7–4.5 (tunable)	$6.6 \times 10^{- 4}$	$\sim 1.5$	$Spectral resolution = 1.8 nm$ at 3.3 μm	$NEP = 1.6 \times 10^{- 14} W / {Hz}^{1 / 2}$
1977 [27]	Proustite (1 cm), collinear, Type-II PM	Krypton laser (752.5), CW, 0.25 W	10 (tunable: 9–11 μm)	$2.3 \times 10^{- 7}$	$\sim 17$	$N_{res} = 500$	$NEP = 3 \times 10^{- 10} W / {Hz}^{1 / 2}$ (on each pixel)
1981 [153]	Proustite (1.85 cm), tangential PM	Dye laser (697), pulse, 2 J/pulse	10.6	$5.69 \times 10^{- 12}$	–	Angular res. $\sim 5 °$	Minimum IR power that can be $detected = 2.12 mW$
1987 [72]	${KNbO}_{3}$ (0.9 cm), temperature tuned noncritical 90° PM	Krypton laser (676.4)	Nd-YAG laser at 1.064	$\sim 2 \times 10^{- 5}$	2.8	Angular res. $\sim 1.5 °$	–
1992 [199]	Urea, Type-II PM,3-D depth imaging (SHG experiment)	Mode-locked ring dye laser (620), 80 fs, 5 MW peak power	0.62	–	–	18 lines/mm, (depth resolution $\sim 10 μm$ )	–
1994 [200]	KDP (3 cm), time gating	SHG of Nd-YAG (532), pulse	Nd-YAG laser at 1.064	$\sim 5 %$	–	1.41 lines/mm, maximum gate delay $\sim 66 ps$	–
1999 [201]	BBO (1 cm), collinear NCPM	Nd-YAG (1064), pulse, $40 MW / {cm}^{2}$	0.852	$\sim 5 %$	0.2	$\sim 200 μm$	–
2000 [137]	BBO (1 cm), non-collinear NCPM, synchronous pump	Nd-YAG (1064), $Q$ -switched	Ti:sapphire laser at 0.852	–	2.4	100 μm	–
2002 [92]	PPLN (2.5 cm), temperature, microlens array	Nd-YAG (1064), $Q$ -switched	1.85	–	2.25 mm object diameter	4.2 lines/mm	–
2007 [44]	PPLN (5 cm), temperature, collinear QPM, raster-scanning	Nd-YAG (1064), $Q$ -switched	OPO at 3.4	$\sim 40 %$ (peak to peak)	60 (max. scan angle)	$50 \times 50 pixels$	Minimum detectable $power = 0.2 nW$
2009 [70]	PPKTP (1 cm), temperature, QPM	$Nd - {YVO}_{4}$ (1342), CW, intracavity	0.765, CW (ECDL)	25%	–	$10 \times 10 pixels$	–
2010 [90]	PPKTP (1 cm), temperature, QPM	$Nd - {YVO}_{4}$ (1342), CW, intracavity	0.766 (halogen)	$\sim 2 \times 10^{- 4}$	$< 1$	$200 \times 1000 pixels$	–
2012 [45]	PPLN (2 cm), temperature tuning, QPM	$Nd - {YVO}_{4}$ (1064), CW, intracavity	3 (tunable from 2.85 to 5 μm)	$\sim 20 %$ (polarized, collinear)	–	$200 \times 100 pixels$	0.2 photons/s/pixel
2012 [162]	PPLN (5 cm), temperature, QPM, synchronous pump	EDFL (1549), pulse	Yb-doped fiber laser at 1.04	$\sim 33.5 %$ (peak to peak)	$\sim 2 mm \times 2 mm$ object area	–	Noise probability per pulse $\sim 8 \times 10^{- 5}$
2013 [202]	PPLN (5 cm), temperature, QPM	Mode-locked Yb-doped laser (1050)	3.39, CW	12.5%	1.5 mm image diameter	$\sim 2 lines / mm$	$1.1 \times 10^{3} counts / s$
2014 [203]	DAST, collinear, difference frequency generation	KTP-OPO (1292)	19.3 THz	–	40 mm object diameter	$\sim 3 mm$	Signal-to-noise ratio $(SNR) = 30$
2014 [204]	PPLN, $x - y$ scanning, microscope setup	$Nd - {YVO}_{4}$ (1064), CW, intracavity	$\sim 2 - 3$	–	–	$\sim 5.5 μm$ (181 lines/mm)	–
2015 [94]	PPLN (2 cm), QPM, non-collinear, hyperspectral	$Nd - {YVO}_{4}$ (1064), CW, intracavity	3.24–3.41	–	$1 {cm}^{2}$ object area	231 μm (PSF) spectral res. $\sim 9 - 30 nm$	–
2015 [172]	PPLN (0.5 cm), QPM, non-collinear	$Nd - {YVO}_{4}$ (1064), CW, intracavity	1.55, $FWHM = 15 nm$	$\sim 10^{- 4}$	$> 1.6$	4 lines/mm	Limited by CCD dark noise
2015 [177]	PPLN (5 cm), QPM, phase imaging	Yb-doped laser (1036)	1.558	$\sim 68 %$	–	–	$3.8 \times 10^{3} counts / s$
2016 [104]	${LiNbO}_{3}$ (1 cm), angle tuning, synchronous	Er-doped fiber laser (1550), pulse	Superconti-nuum, 1.8–2.6	$\sim 1.2 \times 10^{- 5}$ (collinear)	$\sim 1.9 mm$ image diameter	$\sim 55 μm$	–
2016 [170]	PPLN (0.5 cm), QPM, broadband, angular	$Nd - {YVO}_{4}$ (1064), CW	ASE, 1.55, bandwidth $\sim 8 nm$	–	$\sim 4$	–	–
2016 [135]	BBO (0.2 cm), transient imaging	(1510), pulse	0.81	–	$\sim 1 mm$ object diameter	Time res. $\sim 174 fs$ , spatial res. $\sim 11.3 lines / mm$	–
2017 [205]	PPLN (4 cm), QPM, temperature tuning	$Nd - {YVO}_{4}$ (1064), CW, intracavity	Heat lamp 2.9–3.5	$\sim 28 %$ (collinear, polarized)	–	$N_{res} \sim 120 \times 70$	0.57 photons/sec/pixel
2017 [161]	${AgGaS}_{2}$ (1 cm), angle tuning, hyperspectral	Er-doped fiber laser (1550), $n$ s	Superconti-nuum, 2–4.5	$\sim 1.0 \times 10^{- 4}$ (collinear)	14.9 mm object diameter	$\sim 79 μm$ (12.7 lines/mm), $N_{res} \sim 32, 400$	–
2017 [97]	${LiNbO}_{3}$ (1 cm), angle tuning, synchronous	fiber laser (1550), $p$ s	Er–Tm fiber laser 1.877	–	$2.63 {mm}^{2}$ object area	$\sim 23 μm$ , $N_{res} \sim 5000$	–
2018 [124]	${AgGaS}_{2}$ (1 cm), angle tuning, hyperspectral	$Nd - {YVO}_{4}$ (1064), CW, 1.7 W	Globar, 6–8	–	$\sim 21 mm$ object diameter	$\sim 35 μm$ , $N_{res} \sim 4400$ , spectral res. $> 8 {cm}^{- 1}$	–
2018 [169]	PPLN (0.5 cm), non-collinear QPM, thermal gradient	Nd-YAG (1064)	1.554	0.25 (normalized to the case $Δ T = 0 ° C$ )	$\sim 8$ (for $Δ T = 50 ° C$ )	–	–
2018 [95]	PPLN (2 cm), non-collinear QPM, broadband pump	Yb- fiber laser (1064), pulse, $FWHM = 2.7 nm$	Fiber laser at 1.563, CW	$\sim 7 %$ (for 320 W pump peak power)	$\sim 6.5$	$N_{res} = 56 \times 64$	Sensitivit $y \sim 1.3 \times$ commercial InGaAs
2018 [67]	${AgGaS}_{2}$ (1 cm), collinear, angle tuning	$Nd - {YVO}_{4}$ (1064), CW, 3W	QCL, tunable 9.4–12, pulse	$\sim 1.0 \times 10^{- 2}$	$\sim 0.4$	–	$SNR > 10$ (for single pulse)
2018 [179]	${AgGaS}_{2}$ (1 cm), raster-scanning, hyperspectral	$Nd - {YVO}_{4}$ (1064), CW, 3W	QCL, tunable 9.4–12, pulse	$\sim 1.0 \times 10^{- 2}$	$\sim 1.3 mm \times 1.2 mm$ object area	$< 35 μm$ , spectral res. $\sim 1 {cm}^{- 1}$	–
2019 [185]	PPLN (2 cm), non-collinear QPM, object scanning in 3-D OCT imaging	$Nd - {YVO}_{4}$ (1064), CW, intracavity	Superconti-nuum, 3.5–4.7, 1 MHz	$\sim 1 %$	$\sim 1 {cm}^{2}$ object area	$\sim 15 μm$	–
2019 [206]	${LiNbO}_{3}$ (1 cm), electronically synchronous	MOPA (1064), pulse, 1.6 ns	Superconti-nuum, 2–4.2, 1.6 ns, 40 kHz	1%	13 mm object diameter	$< 78.8 μm$	SNR is $\sim 1$ (integration time 0.5 ms)
2019 [167]	${LiNbO}_{3}$ (1 cm), tangential PM, rotation of crystal	Yb- fiber laser (1064), pulse, 20 ps, 80 MHz	Optical parametric oscillator, tunable 2.3–4.1, pulse	0.002% for each pixel over full FoV	10 mm object diameter	$\sim 35 μm$ ( $N_{res} = 64, 000$ ) at 3.1 μm	$SNR = 424$ at the center of image
2019 [207]	${LiNbO}_{3}$ (1 cm), birefringent PM, polychromatic, rotation of crystal	Mode-locked Ti:sapphire (804), 100 fs, 80 MHz	Optical parametric oscillator, tunable 2.7–4, 200 fs	$\sim 10^{- 5}$	$\sim 20$ at 2.851 μm.	$\sim 56 μm$ at 3.206 μm	–

Ajanta Barh	https://orcid.org/0000-0002-8589-0238
Peter John Rodrigo	https://orcid.org/0000-0003-0819-2361
Lichun Meng	https://orcid.org/0000-0001-9787-2195
Christian Pedersen	https://orcid.org/0000-0001-7238-489X
Peter Tidemand-Lichtenberg	https://orcid.org/0000-0002-4988-0526

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Advances in Optics and Photonics