Wavelength-tunable source of pulsed laser radiation for VIS-NIR spectroscopy which consists of a pump source (1) forming bursts of picosecond pulses of high pulse repetition rate, and a synchronously pumped optical parametric oscillator (2). The pump source (1) comprises a solid-state regenerative amplifier (31) having one or two electro-optical switches (32,33) inside its resonator (44). The switches create partial transmission of the resonator for a time interval longer than a resonator roundtrip time, and eject a part of energy of a pulse circulating inside. Bursts of 5-10 ns duration are formed, which are filled with high peak power picosecond pulses. Pulse repetition rate of the order of GHz of pump pulses allows the construction of a compact optical parametric oscillator. The whole set of parameters ensures high energy efficiency, stability and an ability to provide output pulse bursts repeating at up to 10 kHz repetition rate.

A higher-order-mode (HOM) fiber of a fiber laser has step index and guidance diameter (GD) defining wavelength-dependent dispersion characteristics and effective areas for corresponding HOMS of optical signal propagation. One HOM has anomalous dispersion and effective area defining a first wavelength and first power of a pulse optical signal for conversion to a second wavelength and second power by soliton self-frequency shifting (SSFS). By controlling step index and GD, the dispersion and effective area of a HOM are adjusted to bring the second wavelength into a desired range, enabling applications requiring non-conventional fiber laser wavelengths. HOMS may share a predetermined group index and group velocity at wavelengths established by a Raman gain peak to effect wavelength conversion by interpulse and intermodal Raman scattering, which may occur in a cascaded fashion to yield multicolor lasers with desired wavelengths, pulse energies and pulse widths.

A high average and peak power single transverse mode laser system is operative to output ultrashort single mode (SM) pulses in femtosecond-, picosecond- or nanosecond-pulse duration range at a kW to MW peak power level. The disclosed system deploys master oscillator power amplifier configuration (MOPA) including a SM fiber seed, outputting a pulsed signal beam at or near 1030 nm wavelength, and a Yb crystal booster. The booster is end-pumped by a pump beam output from a SM or low-mode CW fiber laser at a pump wavelength in a 1000-1020 nm wavelength range so that the signal and pump wavelengths are selected to have an ultra-low-quantum defect of less than 3%.

An Nd.sup.3+ optical fiber laser and amplifier operating in the wavelength range from 1300 to 1450 nm is described. The fiber includes a rare earth doped optical amplifier or laser operating within this wavelength band is based upon an optical fiber that guides light in this wavelength band. The waveguide structure attenuates light in the wavelength range from 850 nm to 950 nm and from 1050 nm to 1150 nm.

A mid-infrared cascading fiber amplifier device having a source configured to generate a first electromagnetic wave output at a first frequency, a fiber coupled to the source and a pump coupled to the fiber and configured to generate a second electromagnetic wave output at a second frequency, wherein the second frequency is higher than the first frequency and causes the fiber to undergo two or more transitions in response to stimulation by the first electromagnetic wave output at the first frequency, wherein the first transition generates the first electromagnetic wave output approximately at the first frequency and the second transition generates the first electromagnetic wave output approximately at the first frequency.

The present disclosure discloses a 2.8 ?m and 3.5 ?m dual-wavelength mid-infrared fiber laser, which employs 0.98 ?m+1.15 ?m pumping scheme, uses a fiber combiner to combine two pump lights into the double cladding Er-doped fluoride fiber. The Er ions in the ground state are first promoted to .sup.4I.sub.11/2 level by the 0.98 ?m pump light, realizing 2.8 ?m lasing based on .sup.4I.sub.11/2.fwdarw..sup.4I.sub.13/2 transition, and further promoted to .sup.4F.sub.9/2 level by the 1.15 ?m pump light, generating 3.5 ?m lasing based on .sup.4F.sub.9/2.fwdarw..sup.4I.sub.9/2 transition; followed by the 3.5 ?m laser transition, the Er ions would rapidly decay to .sup.4I.sub.11/2 level via non radiative transition, realizing the re-population of .sup.4I.sub.11/2 level, effectively enlarge the population inversion of 2.8 ?m transition, suppressing the self-termination of 2.8 ?m lasing and achieving 2.8 ?m and 3.5 ?m dual-wavelength cascaded lasing output.

A laser device includes a light source device including a semiconductor laser; and a laser cavity irradiated with light from the light source device and including a saturable absorber. A beam waist diameter r of the light that irradiates the laser cavity and an initial transmittance T.sub.0 of the saturable absorber satisfy a relationship of 7.75T.sub.0.sup.47.77T.sub.0.sup.3+3.13T.sub.0.sup.2+0.16T.sub.0+0.74r2.62T.sub.0+0.675.

A mid-infrared cascading fiber amplifier device having a source configured to generate a first electromagnetic wave output at a first frequency, a fiber coupled to the source and a pump coupled to the fiber and configured to generate a second electromagnetic wave output at a second frequency, wherein the second frequency is higher than the first frequency and causes the fiber to undergo two or more transitions in response to stimulation by the first electromagnetic wave output at the first frequency, wherein the first transition generates the first electromagnetic wave output approximately at the first frequency and the second transition generates the first electromagnetic wave output approximately at the first frequency.

A pump system for a high-power holmium-doped fiber optic laser is provided, comprising: a 1.13 micron pumping means composed of: a coreless fiber and a light absorber; high and low reflection Bragg gratings at 1.135 microns, which form a ytterbium fiber laser cavity; high-power 915 nm laser diodes pumping the ytterbium fiber; and a high reflection Bragg grating (HR-FBG) at 2.07 microns; and a 2 micron laser formed by a holmium-doped fiber (HDF) that forms, with the high reflection Bragg grating at 2.07 microns, a holmium-doped fiber laser cavity, where each 915 nm photon of the 915 nm laser diodes that is converted into a 1.13 micron photon releases additional energy in the form of heat.

A mid- to far-infrared solid state Raman laser system comprising a resonator cavity comprising: an input reflector adapted to be highly transmissive for light with a first wavelength in the range of about 3 to about 7.5 micrometers for admitting the first beam to the resonator cavity; and an output reflector adapted to be partially transmissive for light with a second wavelength greater than about 5.5 micrometers for resonating the second wavelength in the resonator and for outputting an output beam, the input reflector further being adapted to be highly reflective at the second wavelength for resonating the second wavelength in the resonator; and a solid state diamond Raman material located in the resonator cavity for Raman shifting the pump beam and generating the second wavelength.