According to an aspect, the present description concerns a frequency-tunable laser source comprising: a set of N elementary sources (101-k), each elementary source being suitable for emitting a beam at a given central frequency (fk); an optical coupler (12) for coupling the beams emitted by each of the elementary sources in order to form a multi-spectral incident beam (B.sub.in) regrouping all the frequencies of the N elementary sources in a same optical beam; a beam splitter (15) for forming, from the incident beam (B.sub.in), a first beam (B.sub.1) and a second beam (B.sub.2), each regrouping all the frequencies of the elementary sources; a first tunable filter (16) for selecting, from the first beam (B.sub.1), a third beam (B.sub.3) at a first frequency (F.sub.j); a second tunable filter (17) for selecting, from the second beam (B.sub.2), a fourth beam (B.sub.4) at a second frequency (F.sub.l); a nonlinear frequency doubling crystal (18) for generating, from the third beam at the first frequency (F.sub.j), a fifth beam (B.sub.5) having a frequency (F.sub.2j) which is twice the first frequency; a nonlinear sum-frequency generation crystal (19) for generating, from the fifth beam coming from the nonlinear frequency doubling crystal and from the fourth beam at the second frequency (F.sub.l), a beam (B.sub.out) having a frequency (F.sub.2j+1) equal to the sum of twice the first frequency (F.sub.2j) and the second frequency (F.sub.l).

An apparatus for producing a single photon can comprise a modulator that modulates the wavelength of a pump beam based on wavelength of an idler photon of a signal/idler photon pair. A wavelength division multiplexer combines the modulated pump beam and the signal photon in a non-linear element to produce an output photon having a preselected wavelength based on signal photon wavelength and a wavelength of the modulated pump beam.

A solid state laser device includes a seed laser that outputs continuous wave laser seed light, a light intensity changeable unit that changes a light intensity thereof and outputs seed pulse light, a CW excitation laser that outputs continuous wave excitation light, an amplifier that amplifies the seed pulse light and outputs amplified light based on an amplification gain increased by the excitation light, a wavelength conversion unit that converts a wavelength of the amplified light and outputs harmonic light, and a light intensity control unit that allows the light intensity changeable unit to output the seed pulse light after a certain time elapsed from an input of an external trigger signal each time the signal is input and output suppression light that suppresses an increase of the amplification gain in a period after an output of the seed pulse light until an input of a next external trigger signal.

An RGB light source for a luminaire projector system includes Red, Green and Blue lasers each outputting a randomly polarized (RP) single mode (SM) light with at least a 4 nm spectral linewidth. The Green laser has a MOPFA-structured pump which outputs a pulsed pump beam at a fundamental wavelength in a 1 ?m wavelength range and further includes a SHG. The SHG includes an LBO nonlinear crystal receiving the pulsed pump beam and outputting a train of pulses of BB Green light. The Red laser is configured with a QCW fiber laser pump and a frequency converter with an LBO nonlinear crystal outputting a train of pulses of red light in a 6xx nm wavelength range.

According to an aspect, the present description concerns a frequency-tunable laser source comprising: a set of N elementary sources (101-k), each elementary source being suitable for emitting a beam at a given central frequency (fk); an optical coupler (12) for coupling the beams emitted by each of the elementary sources in order to form a multi-spectral incident beam (B.sub.in) regrouping all the frequencies of the N elementary sources in a same optical beam; a beam splitter (15) for forming, from the incident beam (B.sub.in), a first beam (B.sub.1) and a second beam (B.sub.2), each regrouping all the frequencies of the elementary sources; a first tunable filter (16) for selecting, from the first beam (B.sub.1), a third beam (B.sub.3) at a first frequency (F.sub.1); a second tunable filter (17) for selecting, from the second beam (B.sub.2), a fourth beam (B.sub.4) at a second frequency (); a nonlinear frequency doubling crystal (18) for generating, from the third beam at the first frequency (F.sub.j), a fifth beam (B.sub.5) having a frequency (F.sub.2j) which is twice the first frequency; a nonlinear sum-frequency generation crystal (19) for generating, from the fifth beam coming from the nonlinear frequency doubling crystal and from the fourth beam at the second frequency (), a beam (B.sub.out) having a frequency (F.sub.2j+1) equal to the sum of twice the first frequency (F.sub.2j) and the second frequency ().

An optical parameter oscillator (OPO) is pumped at pump wavelength .sub.P to resonate at signal wavelength .sub.S. The OPO produces idler radiation at terahertz frequencies .sub.THz=c/.sub.Pc/.sub.S. The pump, signal, and idler radiation are substantially collinear.

A system for generating an optical frequency standard is described. The system comprises a first laser source for generating a first laser output at a first frequency, a first second harmonic generator receiving as an input the first laser output to generate a frequency-doubled first laser output at a doubled first frequency, a second laser source for generating a second laser output at a second frequency different from the first frequency and a second harmonic generator receiving as an input the second laser output to form a frequency-doubled second laser output at a doubled second frequency. The system further includes a two-colour stabilisation arrangement to stabilise a sum of the doubled first and the doubled second frequencies that includes an interaction region incorporating a laser active material having a two-photon transition from a first energy level to a second energy level which receives as an input the frequency-doubled first laser output and the frequency-doubled second laser output where these outputs are selected to together cause the two-photon transition from the first energy level to the second energy level using an intermediate energy level to enhance the two-photon transition rate. The system also includes a detector to detect an indicator of the two-photon transition occurring in the interaction region which generates a frequency stabilisation signal for modifying either the first laser output or the second laser output to stabilise the sum of the doubled first frequency and the doubled second frequency to the two-photon transition based on the indicator and a stabilised optical output generator that includes a sum frequency generator receiving as an input the first laser output and the second laser output to generate a stabilised optical output with a frequency corresponding to the optical frequency standard.

A method and apparatus for analyzing carbon isotope .sup.14C is provided. A carbon isotope analyzer including an isotopic carbon dioxide generator to generate isotopic carbon dioxide from a carbon isotope; a spectrometer including an optical resonator having a pair of mirrors, and a photodetector to determine the intensity of light transmitted from the optical resonator; and a light generator including a light source, a first optical fiber to transmit a light beam from the light source, a second optical fiber for wavelength conversion, the second optical fiber branching from the first optical fiber at a point and combining with the first optical fiber at another point downstream of the branching point, and a non-linear optical crystal to generate light having the absorption wavelength of the isotopic carbon dioxide on the basis of the difference in frequency between light beams transmitted through the optical crystal.

A laser light source includes a nonlinear optical medium and a pump laser source configured to generate a pump laser beam to form a signal beam and an idler beam in the nonlinear optical medium by parametric down conversion. The laser light source further includes a seed light source configured to generate a seed signal beam and/or a seed idler beam having a coherence length lesser than a coherence length of the pump laser beam, and a superpositioning device configured to superposition the seed signal beam and/or the seed idler beam with the pump laser beam for joint coupling into the nonlinear optical medium.

System and methods for the sampling of an optical signal by generating a plurality of copies of the spectrum of the said optical signal including at least one sampling block for the convolution between the optical input spectrum and an optical comb; wherein the said sampling block includes a modulator, and a bias voltage generator, the said sampling block is driven by an electrical comb generator and a phase shifter, the said electrical comb generator being configured to generate a number of N lines, with N from one to infinity, in the radio frequency domain, equally spaced in frequency and locked in phase, the said modulator being configured to generate a plurality of 2N+1 copies of the input spectrum from (i) the signal spectrum and (ii) a number of N lines provided by the said electrical comb generator.