Phasematch curves as well as sensitivity to angular and wavelength misalignment for generation of second-harmonic of 785 nm and 810 nm in Bi(3)BO(6) crystal was calculated. Measurements were done for ...intra-cavity CW SHG in a Ti:Sapphire laser. The BiBO crystal was found to be excellent for this application. Temperature dependance was uncritical for both crystals, while power stability was good. Maximum blue output was 53 mW at 392 nm and 100 mW at 405 nm; corresponding to pump-to-blue optical conversion efficiencies of 0.96% and 1.82% respectively.
We investigate the possibility of improving the beam quality and obtaining high conversion efficiency in nonlinear sum-frequency generation. A 765 nm beam from an external cavity tapered diode laser ...is single-passed through a nonlinear crystal situated in the high intracavity field of a 1342 nm Nd:YVO
4
laser, generating a SFG beam at 488 nm. The ECDL have
M
H
2
=1.9 and
M
V
2
=2.4 and the solid-state laser has
M
2
<1.05. Varying the focusing of the 765 nm beam, the conversion efficiency and the beam quality of the generated 488 nm beam change correspondingly. We show that it is possible to improve the
M
2
of the 488 nm beam to less than 1.3 while preserving a high conversion efficiency of the SFG process.
Mid-infrared integrated quantum photonics is a promising platform for applications in sensing and metrology. However, there are only a few examples of on-chip single-photon sources at these ...wavelengths. These have limited performances with respect to their C-band counterparts. In this work, we demonstrate a new approach to generate heralded single photons in the mid-infrared on a silicon chip. By using a standard C-band pump, the inter-modal spontaneous four-wave mixing enables the generation of the herald idler at 1259.7 nm and the heralded signal at 2015 nm. The idler photon is easily detected with a common infrared single-photon detector while the signal photon is upconverted to visible before its detection. In this way, we are able to operate a mid-infrared source without the need for mid-infrared detectors and laser sources. By measuring a heralded g(2) of 0.23 ± 0.08, we demonstrate the single-photon behavior of the source as well as the feasibility of multi-photon coincidence measurements beyond 2 μm with our setup. The source exhibits a high-intrinsic heralding efficiency of (59 ± 5)%, a maximum coincidence to accidental ratio of 40.4 ± 0.9, and a generation probability of 0.70±0.10W−2.
In this paper the results of a theoretical and experimental investigation of synchronized passive Q-switching of two Nd:YVO4-based solid-state lasers operating at two different wavelengths, is ...described. A V:YAG saturable absorbing material was used as a passive Q-switch performing the synchronization of the two laser fields. This material provides Q-switching operation at both 1064 and 1342nm wavelengths simultaneously, saturating the same energy level. By adjusting the pump power of both lasers, it was possible to optimize the overlap of the two pulse trains and to switch between different states of synchronization. A theoretical model based on rate equations, which has been developed in order to investigate optical performance of the laser system, is in a good agreement with the experimental results. The principle of synchronized Q-switching can lead to new, pulsed all-solid-state light sources at new wavelengths based on sum-frequency mixing processes.
The material V:YAG can work as a saturable absorber both at 1064 and 1342 nm. It is shown in this paper, that the saturation effect is spectrally homogeneous. V:YAG can therefore be used for ...generation of passively synchronized Q-switched pulses at wavelengths hundreds of nanometers apart. First a pump–probe experiment is described, investigating the fundamental cross wavelength coupling. Then the first measurements of synchronized Q-switched pulses using a solid-state passive saturable absorber are presented. Finally a setup containing two different saturable absorbing materials is investigated, showing very stable passive synchronized Q-switching at two distinct wavelengths.
APL Photonics 6, 126103 (2021) Mid infrared integrated quantum photonics is a promising platform for
applications in sensing and metrology. However, there are only few examples of
on-chip single ...photon sources at these wavelengths. These have limited
performances with respect to their C-band counterparts. In this work, we
demonstrate a new approach to generate heralded single photons in the mid
infrared on a silicon chip. By using a standard C-band pump, the inter-modal
spontaneous four wave mixing enables the generation of the herald idler at
1259.7 nm and the heralded signal at 2015 nm. The idler photon is easily
detected with a common infrared single photon detector while the signal photon
is upconverted to the visible before its detection. In this way, we are able to
operate a mid infrared source without the need of mid infrared detectors and
laser sources. By measuring a heralded $g^{(2)}$ of $0.23 \, \pm \, 0.08$ we
demonstrate the single photon behaviour of the source as well as the
feasibility of multi-photon coincidence measurements beyond 2 $\mu$m with our
setup. The source exhibits a high intrinsic heralding efficiency of $(59 \, \pm
\,5)\%$, a maximum coincidence to accidental ratio of $40.4 \, \pm \, 0.9$ and
a generation probability of $\left( 0.72 \, \pm \, 0.10 \right)$ W$^{-2}$.
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