An optical configuration including axiconical elements that serve as parts of a resonator or an optical chain of an amplifier for an active laser volume with a large transverse dimension. The system may include a single-fold or multiple-folds axiconical elements. One of the system's advantages is providing the means to produce, even with a stable resonator, a high-quality and well-controlled beam, utilizing efficiently a wide active laser medium.

External cavity laser systems are described that can operate with essentially no mode hopping. One example configuration of the laser system includes a semiconductor laser device, a folded cavity external to the semiconductor laser device, where at the semiconductor laser device is positioned at a fold in the folded cavity. In this configuration, at least one mirror is positioned in the folded cavity to enable sustained propagation of light within the folded cavity, and at least two polarization elements are positioned in the folded external cavity. The polarization elements cause a polarization state of the light that impinges in different directions on each semiconductor laser device that is positioned at a fold to be orthogonal to one another, thus eliminating or substantially reducing mode hopping in the laser output.

Apparatus and methods for producing ultrashort optical pulses are described. A high-power, solid-state, passively mode-locked laser can be manufactured in a compact module that can be incorporated into a portable instrument. The mode-locked laser can produce sub-50-ps optical pulses at a repetition rates between 200 MHz and 50 MHz, rates suitable for massively parallel data-acquisition. The optical pulses can be used to generate a reference clock signal for synchronizing data-acquisition and signal-processing electronics of the portable instrument.

A folded slab waveguide laser having a hybrid waveguide-unstable resonator cavity. Multiple slab waveguides of thickness t supporting vertical waveguide modes are physically arranged above one another in a stack and optically arranged in series through one or more cavity folding assemblies with curved mirrors. A gain medium such as a gas is arranged in each slab. Each cavity folding assembly is designed to redirect the radiation beam emitted from one slab waveguide into the next waveguide and also at the same time to provide a focus for the radiation beam so that a selected vertical waveguide mode (or modes) is (or are) coupled efficiently into the next slab.

A laser resonator includes a pair of optical elements forming a first optical path having a focused beam waist, one or more mirrors forming a second optical path of approximately parallel light connected to the first optical path, and a laser medium arranged in the second optical path. Induced emission light generated from the laser medium reciprocates or circles in a path formed by the first optical path and the second optical path. A distance between the pair of optical elements is adjustable, and a beam diameter at the second optical path is adjusted by adjusting the distance between the pair of optical elements.

Apparatus and methods for producing ultrashort optical pulses are described. A high-power, solid-state, passively mode-locked laser can be manufactured in a compact module that can be incorporated into a portable instrument. The mode-locked laser can produce sub-50-ps optical pulses at a repetition rates between 200 MHz and 50 MHz, rates suitable for massively parallel data-acquisition. The optical pulses can be used to generate a reference clock signal for synchronizing data-acquisition and signal-processing electronics of the portable instrument.

The invention relates to a method of generating frequency-tripled laser radiation (THG). It is the object of the invention to demonstrate an efficient approach to generating frequency-tripled laser radiation. The method according to the invention comprises the following method steps: providing a first laser radiation at a fundamental frequency, coupling the first laser radiation into an optical resonator, which is resonant at the fundamental frequency, generating a second laser radiation by second-harmonic generation of the first laser radiation in a type-I process in a first nonlinear optical crystal (3), which is located in the optical resonator, wherein the second laser radiation has a polarization direction, rotating the polarization direction of the second laser radiation, preferably by an angle of substantially 90, and generating a third laser radiation by generating the sum frequency of the first and second laser radiations in a type-I process in a second nonlinear optical crystal (9), which is likewise located in the optical resonator. The invention also relates to a device for generating frequency-tripled laser radiation.

Provided herein are systems and methods of manufacture and operation for a compact laser to achieve high-intensity output pulses. These compact laser resonators and methods rely upon separate and distinct functions of the laser resonator to be operated in balance such that the functions, while deleterious when separate are supportive of laser generation and growth when combined within a small volume laser resonator as described herein. The combined elements of the described laser resonator include a delicate balance that allows the laser to operate between plane-parallel operation and unstable operation. This operation mode further allows distinct methods of construction and operation that allow the compact laser to be reliably assembled and tested during assembly. Therefore, despite requiring a delicate balance of disparate elements, the described laser resonator results in a compact robust laser.

Apparatus and methods for producing ultrashort optical pulses are described. A high-power, solid-state, passively mode-locked laser can be manufactured in a compact module that can be incorporated into a portable instrument. The mode-locked laser can produce sub-50-ps optical pulses at a repetition rates between 200 MHz and 50 MHz, rates suitable for massively parallel data-acquisition. The optical pulses can be used to generate a reference clock signal for synchronizing data-acquisition and signal-processing electronics of the portable instrument.

A laser transmitter assembly for use in a Coherent Doppler Wind Lidar (CDWL) system includes a telescope/scanner assembly, a receiver, and a master oscillator crystal and a power amplifier crystal each constructed of Ho:YAG. The crystals are end-pumped to transmit an output beam through the telescope/scanner assembly with a high repetition rate of 200-300 Hz and 35 mJ of energy. As part of the CDWL system, a pump laser end-pumps the master oscillator and power amplifier crystals using a pump beam having a nominal wavelength of 1.905 m. A seed laser transmits a seeding beam into the master oscillator crystal at a nominal wavelength of 2.0965 m. The telescope/scanner assembly transmits the generated laser beam through an atmosphere toward a scene of interest, collects a backscattered return signal, and communicates the backscattered return signal to the receiver during operation of the CDWL system.