A laser system involving coupled distributed resonators disposed serially, with the lasing gain medium located in the main resonator and the output of that resonator being directed into a free space resonator, such that the main resonator output mirror is effectively the free space resonator. The distributed resonators end mirrors are retroreflectors. Interference occurs between light traveling towards the remote mirror of the free space resonator and light reflected therefrom, generating regions of high reflectivity. The coupling of the free space resonator to the regions of high reflectivity of the free space resonator enables the first resonator to lase efficiently, even though the true reflectivity of the main resonator output mirror outside of those regions is insufficient to enable efficient lasing, if at all. This coupled resonator structure enables lasing to occur with a high field of view and the high gain engendered by the high reflectivity regions.

A femtosecond pulse laser apparatus includes a pump light source configured to provide a pump light, a gain medium configured to obtain a gain of a laser light using the pump light, a first curved mirror and a second curved mirror, which are provided at both sides of the gain medium, an output mirror configured to transmit a portion of the laser light and reflect the other portion of the laser light to the gain medium, a mode locking portion configured to generate a femtosecond pulse of the laser light, and an acoustic wave generator configured to provide an acoustic wave into the gain medium so as to adjust self-phase modulation of the laser light.

A laser system involving coupled distributed resonators disposed serially, with the lasing gain medium located in the main resonator and the output of that resonator being directed into a free space resonator, such that the main resonator output mirror is effectively the free space resonator. The distributed resonators end mirrors are retroreflectors. Interference occurs between light traveling towards the remote mirror of the free space resonator and light reflected therefrom, generating regions of high reflectivity. The coupling of the free space resonator to the regions of high reflectivity of the free space resonator enables the first resonator to lase efficiently, even though the true reflectivity of the main resonator output mirror outside of those regions is insufficient to enable efficient lasing, if at all. This coupled resonator structure enables lasing to occur with a high field of view and the high gain engendered by the high reflectivity regions.

A method for expanding a tuning range of an all-solid-state continuous-wave single-frequency laser is provided. The method includes inserting a nonlinear frequency-doubling crystal into a laser resonant cavity, and converting a part of intra-cavity fundamental-frequency light to frequency-doubled light by the nonlinear frequency-doubling crystal, outputting the generated frequency-doubled light and the fundamental-frequency light together from the laser resonant cavity, and separating the two via a spectroscope. The method also includes splitting a part of the fundamental-frequency light reflected by the spectroscope through an optical beam-splitter, and outputting the remaining part of the fundamental-frequency light as a main laser. A cavity length of the laser resonant cavity is changed by adjusting a voltage loaded on a piezoelectric ceramic of the all-solid-state continuous-wave single-frequency laser, thereby achieving continuous frequency-tuning of the all-solid-state continuous-wave single-frequency laser.

A divided-pulse laser regeneration amplification apparatus includes: a signal light coupling component including a first half-wave plate, a first polarization beam splitter, a first Faraday rotator and a second half-wave plate placed in sequence; and a divided-pulse laser regeneration amplification component including a second polarization beam splitter and a third reflector, the second polarization beam splitter is adjacent to the second half-wave plate and is in a same column as the third reflector and the second half-wave plate; a first quarter-wave plate, a Pockels cell and a first reflector are successively arranged on a first side of the second polarization beam splitter, and a third half-wave plate, a first pulse polarization separation component and a first non-linear pulse amplification component are successively arranged on a second side of the second polarization beam splitter.

A laser apparatus is provided, which includes an optical reflection and gain unit, an optical modulation unit and a polarizing selection unit. The optical reflection and gain unit includes a gain medium and at least two dichroic surfaces, and is configured to generate a laser beam. The optical modulation unit and the optical reflection and gain unit form a cavity, and the optical modulation unit is configured to adjust phase boundary conditions of the cavity. The optical modulation unit includes portions that respectively correspond to optical phase boundaries in the cavity, so as to allow an optical field in the cavity to pass through the optical modulation unit at least twice. The polarizing selection unit is disposed between the optical reflection and gain unit and the optical modulation unit, and is configured to adjust the polarizing direction of the optical field incident to the optical modulation unit.

The present disclosure provides a method of optimising an optical system of a mode-locked laser oscillator or a regenerative, multi-pass or single pass amplifier. The method may include the steps of identifying crystallographic axes of an active laser gain medium crystal, cutting the crystal, and orienting the crystal in the optical system in a predetermined orientation relative to a propagation vector of a laser pulse depending on the required output of the optical system.

A frequency converter for converting a single mode input beam at a fundamental frequency to an output beam at a converted frequency is configured with a plurality of spaced optical components defining a resonant cavity. The optical components shape the input beam with at least one beam waist in the cavity. The frequency converter further includes a non-linear crystal located within the cavity in either a divergent beam with a Rayleigh range smaller than a cavity round trip length so that a center of the crystal is spaced from the beam waist along a beam path, or in a collimated beam with a Rayleigh range greater than the cavity round trip length.

A laser system involving coupled distributed resonators disposed serially, with the lasing gain medium located in the main resonator and the output of that resonator being directed into a free space resonator, such that the main resonator output mirror is effectively the free space resonator. The distributed resonators end mirrors are retroreflectors. Interference occurs between light traveling towards the remote mirror of the free space resonator and light reflected therefrom, generating regions of high reflectivity. The coupling of the free space resonator to the regions of high reflectivity of the free space resonator enables the first resonator to lase efficiently, even though the true reflectivity of the main resonator output mirror outside of those regions is insufficient to enable efficient lasing, if at all. This coupled resonator structure enables lasing to occur with a high field of view and the high gain engendered by the high reflectivity regions.

An intra-cavity frequency-tripled OPS laser has a laser-resonator including two optically nonlinear crystals arranged for type-I frequency conversion. One of the crystals generates horizontally polarized second-harmonic radiation from vertically plane-polarized fundamental-wavelength radiation circulating in the laser-resonator. A birefringent filter is located between the optically nonlinear crystals. The birefringent filter selects the fundamental-wavelength, establishes the vertical polarization-orientation, and selectively rotates the polarization-orientation of the second-harmonic radiation from horizontal to vertical. The vertically polarized fundamental and second-harmonic radiations are type-I sum-frequency mixed by the other optically nonlinear crystal.