F. Steinlechner, N. Hermosa, V. Pruneri, and J. P. Torres
Abstract
Coherent frequency conversion of structured light, i.e. the ability to manipulate the carrier frequency of a wave front without distorting its spatial phase and intensity profile, provides the opportunity for numerous novel applications in photonic technology and fundamental science. In particular, frequency conversion of spatial modes carrying orbital angular momentum can be exploited in sub-wavelength resolution nano-optics and coherent imaging at a wavelength different from that used to illuminate an object. Moreover, coherent frequency conversion will be crucial for interfacing information stored in the high-dimensional spatial structure of single and entangled photons with various constituents of quantum networks. In this work, we demonstrate frequency conversion of structured light from the near infrared (803 nm) to the visible (527 nm). The conversion scheme is based on sum-frequency generation in a periodically poled lithium niobate crystal pumped with a 1540-nm Gaussian beam. We observe frequency-converted fields that exhibit a high degree of similarity with the input field and verify the coherence of the frequency-conversion process via mode projection measurements with a phase mask and a single-mode fiber. Our results demonstrate the suitability of exploiting the technique for applications in quantum information processing and coherent imaging.
Realization and characterization of single-frequency tunable 637.2 nm high-power laser
J. Wang, J. Bai, J. He, and J. Wang
Abstract
We report the preparation of narrow-linewidth 637.2 nm laser device by single-pass sum-frequency generation (SFG) of two infrared lasers at 1560.5 nm and 1076.9 nm in PPMgO:LN crystal. Over 8.75 W of single-frequency continuously tunable 637.2 nm laser is realized, and corresponding optical-optical conversion efficiency is 38.0%. We study the behavior of crystals with different poling periods. The detailed experiments show that the output red lasers have very good power stability and beam quality. This high-performance 637.2 nm laser is significant for the realization of high power ultra-violet (UV) 318.6 nm laser via cavity-enhanced frequency doubling. Narrow-linewidth 318.6 nm laser is important for Rydberg excitation of cesium atoms via single-photon transition.
Upconversion detector for range-resolved DIAL measurement of atmospheric CH4
L. Meng, A. Fix, M. Wirth, L. Høgstedt, P. Tidemand-Lichtenberg, C. Pedersen, & P. J. Rodrigo
Abstract
We demonstrate a robust, compact, portable and efficient upconversion detector (UCD) for a differential absorption lidar (DIAL) system designed for range-resolved methane (CH4) atmospheric sensing. The UCD is built on an intracavity pump system that mixes a 1064 nm pump laser with the lidar backscatter signal at 1646 nm in a 25-mm long periodically poled lithium niobate crystal. The upconverted signal at 646 nm is detected by a photomultiplier tube (PMT). The UCD with a noise equivalent power around 127 fW/Hz1/2 outperforms a conventional InGaAs based avalanche photodetector when both are used for DIAL measurements. Using the UCD, CH4 DIAL measurements have been performed yielding differential absorption optical depths with relative errors of less than 11% at ranges between 3 km and 9 km.
Narrow linewidth 2 μm optical parametric oscillation in periodically poled LiNbO3 with volume Bragg grating outcoupler
M. Henriksson, L. Sjöqvist, V. Pasiskevicius and F. Laurell
Abstract
An optical parametric oscillator using a periodically poled LiNbO3 crystal and a volume Bragg grating output coupler is presented. Signal and idler wavelengths of 2008 and 2264 nm were generated from the 1064 nm Nd:YVO4 pump laser. The Bragg grating was reflecting in a narrow band around 2008 nm, creating a purely singly resonant cavity. Signal and idler linewidths of approximately 0.44 and 0.72 nm, respectively, were measured. This is a reduction of 80 and 60 times compared to when using a mirror as output coupler. A total output energy of 156 μJ was measured with 47% slope efficiency.
High-power, variable repetition rate, picosecond optical parametric oscillator pumped by an amplified gain-switched diode
F. Kienle, K. K. Cheng, S. Alam, C. B. E. Gawith, J. I.Mackenzie, D. C. Hanna, D. J. Richardson, and D. P. Shepherd
Abstract
We demonstrate a picosecond optical parametric oscillator (OPO) that is synchronously pumped by a fiber-amplified gain-switched laser diode. At 24W of pump power, up to 7.3W at 1.54μm and 3.1W at 3.4μm is obtained in separate output beams. The periodically poled MgO-doped LiNbO3 OPO operates with 17ps pulses at a fundamental repetition rate of 114.8MHz but can be switched to higher repetition rates up to 1GHz. Tunabilty between 1.4μm and 1.7μm (signal) and 2.9μm and 4.4μm (idler) is demonstrated by translating the nonlinear crystal to access different poling-period gratings and typical M2 values of 1.1 by 1.2 (signal) and 1.6 by 3.2 (idler) are measured at high power for the singly resonant oscillator.
A picosecond Optical Parametric Oscillator synchronously pumped by an amplified gain-switched laser diode
F. Kienle, K. K. Cheng, S. Alam, C. B. E. Gawith, J. I.Mackenzie, D. C. Hanna, D. J. Richardson, and D. P. Shepherd
Abstract
We demonstrate a picosecond optical parametric oscillator synchronously pumped by a fiber-amplified gain-switched laser diode. Up to 7.3W at 1.54µm and 3.1W at 3.4µm is obtained at pulse repetition rates between 114.8 and 918.4MHz.
F. Kienle, P. S. Teh, S. Alam, C. B. E. Gawith, D. C. Hanna, D. J. Richardson, and D. P. Shepherd
Abstract
We report a high-energy optical parametric oscillator (OPO) synchronously-pumped by a 7.19MHz, Yb-fiber-amplified, picosecond, gain-switched laser diode. The 42m long ring cavity maintains a compact design through the use of an intra-cavity optical fiber. The periodically-poled MgO-doped LiNbO3 OPO provides output pulse energies as high as 0.49μJ at 1.5μm (signal) and 0.19μJ at 3.6μm (idler). Tunability from 1.5μm to 1.7μm and from 2.9μm to 3.6μm is demonstrated and typical M2-values of 1.3 by 1.5 and 1.9 by 2.8 are measured for the signal and idler, respectively, at high power.
F. Kienle, D. Lin, S. Alam, H. S. S. Hung, C. B. E. Gawith, H. E. Major, D. J. Richardson, and D. P. Shepherd
Abstract
We investigate the performance of a magnesium-oxide-doped periodically poled lithium niobate crystal (MgO:PPLN) in an optical parametric oscillator (OPO) synchronously pumped by 530nm, 20ps, 230MHz pulses with an average power of up to 2W from a frequency-doubled, gain-switched LD seed and a multistage Yb:fiber amplifier system. The OPO produces 165mW (signal, 845nm) and 107mW (idler, 1421nm) of average power for 1W of pump power and can be tuned from 800 to 900nm (signal) and 1.28 to 1.54m (idler). Observations of photorefraction and green-induced infrared absorption in different operational regimes of the MgO:PPLN OPO are described and the role of peak intensity and average power are investigated, both with the aim to find the optimal operating regime for pulsed systems.
Optical Parametric Oscillator within 2.4–4.3 μm Pumped with a Nanosecond Nd:YAG Laser
D. B. Kolker, R. V. Pustovalova, M. K. Starikova, A. I. Karapuzikov, A. A. Karapuzikov, O. M. Kuznetsov, and Yu. V. Kistenev
Abstract
An optical parametric oscillator has been designed on the basis of MgO:PPLN periodic structure. A compact nanosecond Nd:YAG laser has been used as a pump source at 1.053 μm. The pump pulse length is 5–7 ns at a maximum pulse energy of 300 μJ and a frequency of 1000–5000 Hz. The oscillation threshold is 22 μJ at 3 μm and 48 μJ at 4.3 μm. The maximum conversion efficiency from incident pump power to the idler output is 3.9%.
M. Vainio, M. Merimaa, L. Halonen, and K. Vodopyanov
Abstract
We report a degenerate femtosecond optical parametric oscillator (OPO) that is synchronously pumped by a mode-locked Ti:sapphire laser at 1 GHz repetition rate. The OPO produces an 85 nm (10 THz) wide frequency comb centered at 1.6 μm. Stable long-term operation with >100mW of average output power has been achieved.
