Nonlinear Optical Crystals: A Complete Survey

By exploiting nonlinear optical effects, a technology of unprecedented flexibility for the production of tunable coherent light has been developed. Referred to as optical parametric generation, it provides sources with spectral coverage extending all the way from the ultraviolet to the mid-infrared, and with temporal coverage extending over all time domains from the femtosecond pulse to the continuous wave. Such sources generate coherent light of outstanding optical quality and are now finding wide-ranging applications.

https://science.sciencemag.org/content/sci/286/5444/1513.full.pdf

Parametric Generation of Tunable Light from Continuous-Wave to Femtosecond Pulses

A tunable, singley-resonant optical parametric oscillator provides femtosecond light pulses in the infrared wavelength band. The oscillator includes an internally mounted thin crystal of KTiOPO 4 which is synchronously pumped by femtosecond pulses from a colliding-pulse passively mode-locked dye laser. Rotation of the crystal varies the wavelength of the oscillator. Prisms within the oscillator cavity control group velocity dispersion to limit pulse width, and the oscillator as stabilized by a feedback network which varies the length of the cavity in response to spectral changes.

Broadly tunable high repetition rate femtosecond optical parametric oscillator

Since the proof-of-principle demonstration of optical parametric amplifier to efficiently amplify chirped pulses in 1992, optical parametric chirped pulse amplification (OPCPA) became a widely recognized and rapidly developing technique for high-power femtosecond pulse generation. In the meantime, we are witnessing an exciting progress in the development of powerful and ultrashort pulse laser systems that employ chirped pulse parametric amplifiers. These systems cover a broad class of femtosecond lasers, with output power ranging from a few gigawatts to hundreds of terawatts, with a potential of generating few-optical-cycle pulses at the petawatt power level. In this paper, we discuss the main issues of optical parametric chirped pulse amplification and overview recent progress in the field.

Trends in chirped pulse optical parametric amplification

We report on the generation of ultrashort tunable pulses with a cavityless traveling-wave scheme consisting of a parametric superfluorescence seed source and a parametric amplifier. We show that the traveling-wave approach, with its advantages of simplicity and direct generation of tunable energetic single pulses, can be used in the femtosecond regime, and to this end we discuss the performances that were obtained with pump pulses of ≈1-ps and 200-fs duration at wavelengths of 0.53 and 0.6 μm, respectively. Of particular interest is the β-barium borate-based traveling-wave parametric generator (type-II phase matching), since it offers the possibility of generating nearly transform-limited pulses that are continuously tunable within a wide spectral range to as high as 3 μm in the IR. With a diffraction-limited pump at 0.53 μm. we obtained tunable pulses in a 1.2× diffraction-limited beam, which could be focused, with an f/20 optics lens, to an intensity of 1013 GW/cm2. A temperature-tuned lithium triborate-based femtosecond parametric generator, with its smaller group-velocity dispersion and absence of walk-off, can operate at a pump energy of as low as 30 μJ in a 200-fs pulse.

Traveling-wave parametric generation of widely tunable, highly coherent femtosecond light pulses

An experimental and theoretical investigation is made of energy conversion in the three-photon parametric interaction of ultrashort light packets Calculations are made both in the constant pump field approximation and for strong energy exchange between packets A parametric two-stage oscillator generating ultrashort light pulses is described: it has an energy conversion efficiency of 12%, a line width of the output radiation of 4–5 cm–1, and a high pulse repetition frequency (up to 25 Hz) A parametric small-signal gain of 109–1010 can be achieved The competition between stimulated Raman scattering (STRS) and stimulated parametric scattering, observed in a number of nonlinear crystals (α-HIO3, KDP, LiIO3), is discussed The characteristics of picosecond optical parametric oscillators (OPO's) using α-HIO3, KDP, LiIO3, and LiNbO3 crystals are given An automatic measuring system incorporating amplitude analyzers, a data terminal, and a computer has been developed to investigate the energy and temporal characteristics

Parametric excitation of light in the picosecond rang

Parametric light amplification and oscillation in KDP with mode-locked pump

Three-photon parametric interaction of ultrashort light pulses in KDP and α-HIO3 crystals is investigated. The study is carried out without the limitation of the given-pump-field approximation.

Features of three-photon parametric interaction of ultrashort light packets in the nonlinear amplification regime

The results are given of a theoretical and experimental investigation of three-photon parametric amplification and generation of ultrashort light pulses in KDP and α-HIO3 crystals. It is shown that parametric amplifiers can be used in spectroscopy to determine the shape and duration of ultrashort weak optical signals. Commissioning of a continuously tunable optical parametric oscillator with a high pulse repetition frequency (up to 25 Hz) is reported.

https://iopscience.iop.org/article/10.1070/QE1976v006n04ABEH011142/pdf

Parametric amplification and generation of ultrashort light pulses for spectroscopic applications

An experimental investigation was made of the energy and spectral characteristics of single-pass parametric generation of light in an α-HIO3 crystal pumped with ultrashort pulses. This crystal produced continuously tunable radiation (λ = 0.71–1.115 μ) of 2×10–4 J energy. The angular structure of the parametric generation spectrum was determined.

V. I. Kabelka

Papers

Parametric excitation of light in the picosecond rang

Parametric light amplification and oscillation in KDP with mode-locked pump

Features of three-photon parametric interaction of ultrashort light packets in the nonlinear amplification regime

Parametric amplification and generation of ultrashort light pulses for spectroscopic applications

Single-pass parametric generation of light in an α-HIO3 crystal pumped with ultrashort pulses