Paolo Dallocchio

Compact, 1.5 mJ, 450 MHz, CdSiP 2 picosecond optical parametric oscillator near 6.3 μm

We report a compact, efficient, high-energy, and high-repetition-rate mid-IR picosecond optical parametric oscillator (OPO) based on the new nonlinear material CdSiP(2) (CSP). The OPO is synchronously pumped by a master oscillator power amplifier system at 1064.1 nm, providing 1 μs long macropulses constituting 8.6 ps micropulses at 450 MHz, and it can be tuned over 486 nm across 6091-6577 nm, covering the technologically important wavelength range for surgical applications. Using a compact (∼30 cm) cavity and improved, high-quality nonlinear crystal, idler macropulse energy as high as 1.5 mJ has been obtained at 6275 nm at a photon conversion efficiency of 29.5%, with >1.2 mJ over more than 68% of the tuning range, for an input macropulse energy of 30 mJ. Both the signal and idler beams are recorded to have good beam quality with a Gaussian spatial profile, and the extracted signal pulses are measured to have durations of 10.6 ps. Further, from the experimentally measured transmission data at 1064 nm, we have estimated the two-photon absorption coefficient of CSP to be β=2.4 cm/GW, with a corresponding energy bandgap, E(g)=2.08 eV.

210-

A single-pass two-stage Nd:YVO4 amplifier was used to increase the energy of a 7.7-ps seed pulse from < 1 nJ to 210 muJ (11-ps time duration), maintaining the input spatial quality of the pulse. The laser-diode side-pumped grazing-incidence Nd:YVO4 slab amplifier was optimized for minimum amplified spontaneous emission noise and for maximum energy extraction, with single-pass small-signal gain of 59 dB. Diffraction-limited operation up to 1 kHz is possible. Conversion efficiency of 75 % at 532 nm and 40% at 266 nm was observed.

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We report a compact, efficient, high-energy and high-repetition-rate mid-infrared picosecond optical parametric oscillator (OPO) based on a new nonlinear material CdSiP2. The OPO is synchronously pumped by a master-oscillator power-amplifier system at 1064.1 nm, providing 1-μs-long macro-pulses constituting 8.6 ps micro-pulses at 450 MHz, and can be tuned over 486 nm across 6091-6577 nm, covering the technologically important wavelength range for surgical applications. Using a compact cavity (~30 cm) and a CdSiP2 crystal, idler macro-pulse energy as high as 1.5 mJ has been obtained at 6275 nm, for an input energy of 30 mJ. The extracted signal pulses have durations of 10.6 ps.

J Picosecond Pulses From a Quasi-CW Nd:YVO

A single pass, side pumped grazing incidence Nd:YVO₄ amplifier, optimized for minimum ASE noise, was used to increase the energy of 10-ps mode-locking seed pulses from 1 nJ to 210 muJ, with M²=1.3.

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We report a compact, efficient, 1.5 mJ, 450 MHz, mid-IR picosecond OPO based on CdSiP2, synchronously-pumped at 1064 nm, covering the technologically important wavelength range of 6091-6577 nm for surgical applications.

Grazing-Incidence Two-Stage Slab Amplifier Package

We report a compact, efficient, 1.5 mJ, 450 MHz, mid-IR picosecond OPO based on CdSiP2, synchronously-pumped at 1064 nm and tunable across 6091-6577 nm, covering the technologically important wavelength range for surgical applications.

High-energy 450-MHz CdSiP2 picosecond optical parametric oscillator near 6.3 μm for biomedical applications

Many industrial and scientific applications require extremely short (≪ 1 ns) high peak power (≫ 100 kW) laser pulses. A sub-ns passively Q-switched composite Yb:YAG/Cr4+:YAG microchip laser was reported recently, operating at up to 3.5 kHz with 175 µJ pulse energy [1]. Owing to extremely high intracavity power density and reliability issues, a different approach relying on a moderate-energy high-frequency oscillator and a single amplifier stage looks more flexible and power-scalable.