The invention relates to a frequency conversion arrangement (100) for optimising properties of a harmonic of a laser, in particular a beam profile and/or a long-term stability, the arrangement comprising:—a first non-linear crystal (X1), which is designed to convert a first wavelength (λ1) partially into a second wavelength (λ2); and—an optical unit, which in particular comprises at least one prism (P), which is designed in such a way as to influence the main axes (x1, y1, x2, y2) of the beam profiles of the first wavelength (λ1) and/or the second wavelength (λ2) differently; and—a second non-linear crystal (X2), which is designed in such a way as to generate a third wavelength (λ3) from the unconverted part of the first wavelength (λ1) and/or the second wavelength (λ2), the second non-linear crystal (X2) having an entry face (A1) and an exit face (A2), and the exit face (A2) running obliquely to the entry face (A1).

A nonlinear crystal grating assembly including two integral nonlinear crystal grating structures having inverted crystal axes and having parallel spaced-apart mesas with predetermined mesa widths arranged such that, when assembled in an interdigitated configuration, the mesas of the two grating structures form an alternating grating pattern that is aligned with a propagation direction of input light, thereby creating a periodic structure for quasi-phase-matching (QPM). The nonlinear crystal grating structures are formed using strontium tetraborate, lithium triborate or another nonlinear crystal material. The nonlinear crystal grating assembly is utilized in a laser assembly in which fundamental wavelengths are doubled and/or summed using intermediate frequency conversion stages, and then a final frequency converting stage utilizes the nonlinear crystal grating assembly to double or sum one or more intermediate light beam frequencies to generate laser output light at high power and photon energy levels. A method and inspection system are also described.

An optical element includes Strontium tetraborate SrB.sub.4O.sub.7 (SBO) crystal plates that are cooperatively configured to create a periodic structure for quasi-phase-matching (QPM) is used in the final frequency converting stage of a laser assembly to generate laser output light having a wavelength in the range of 125 nm to 183 nm. One or more fundamental light beams having fundamental wavelengths between 1 and 1.1 μm are doubled and/or summed using multiple intermediate frequency conversion stages to generate one or more intermediate light beam frequencies (e.g., second through eighth harmonics, or sums thereof), and then the final frequency converting stage utilizes the optical element to either double a single intermediate light beam frequency or to sum two intermediate light beam frequencies to generate the desired laser output light at high power and photon energy levels. A method and inspection system incorporating the laser assembly is also described.

An emission enhancement structure having at least one energy augmentation structure; and an energy converter capable of receiving energy from an energy source, converting the energy and emitting therefrom a light of a different energy than the received energy. The energy converter is disposed in a vicinity of the at least one energy augmentation structure such that the emitted light is emitted with an intensity larger than if the converter were remote from the at least one energy augmentation structure. Also described are various uses for the energy emitters, energy augmentation structures and energy collectors in a wide array of fields, including various adhesives applications.

An emission enhancement structure having at least one energy augmentation structure; and an energy converter capable of receiving energy from an energy source, converting the energy and emitting therefrom a light of a different energy than the received energy. The energy converter is disposed in a vicinity of the at least one energy augmentation structure such that the emitted light is emitted with an intensity larger than if the converter were remote from the at least one energy augmentation structure. Also described are various uses for the energy emitters, energy augmentation structures and energy collectors in a wide array of fields, such as color enhancement, and color enhancement structures containing the same.

An apparatus includes a photodetector and a memristor coupled to the photodetector. The photodetector is configured to receive and convert optical signals to electrical signals to program the memristor to an on or off state. The apparatus further includes a ring resonator coupled to the memristor and configured to modulate light based on the on or off state of the memristor.

Embodiments of the present invention relate to methods and apparatus for detecting atmospheric nitric oxide (NO) at signal levels capable of distinguishing the NO isotopologues. More particularly, embodiments of the present invention relate to methods and apparatus for a single photon laser induced fluorescence (LIF) sensor that pumps a vibronic transition near 215 nm and observes the resulting red shifted fluorescence from about 255 to about 267 nm. Embodiments of the present system uses a NO-LIF measurement fiber-amplified laser apparatus capable of: generating laser linewidth that is sufficiently narrow to resolve the Doppler broadened NO spectrum at room temperature and thereby achieve high signal levels and distinguish the NO isotopologues; generating laser repetition rate sufficient to enable single-photon counting of the fluorescence signal; and having size, weight and environmental robustness allowing for integration onto airborne platforms.

A system for nonlinear frequency conversion includes an acousto-optic modulator for diffracting a portion of an input laser beam as a first-order beam and transmitting a non-diffracted portion of the input laser beam as a zeroth-order beam. The system also includes a nonlinear crystal arranged to receive and frequency convert each of the zeroth-order and first-order beams to generate two respective frequency-converted laser beams, whereby, when the acousto-optic modulator changes the average-power ratio between the zeroth-order and first-order beams, variations of the heat load in the nonlinear crystal are minimized. Either one of the two frequency-converted laser beams may be used as an output laser beam of the system, while the other one of the two frequency-converted laser beams serves to stabilize the heat load in the nonlinear crystal when the acousto-optic modulator is operated to change the average power in the output laser beam.

An apparatus includes a photodetector and a memristor coupled to the photodetector. The photodetector is configured to receive and convert optical signals to electrical signals to program the memristor to an on or off state. The apparatus further includes a ring resonator coupled to the memristor and configured to modulate light based on the on or off state of the memristor.

The invention discloses a visible laser apparatus including a linear cavity. The linear cavity includes along the first direction: a first optical component, a gain medium, a second optical component, a Raman crystal, a double-harmonic crystal and a third optical component. The first optical component receives an incident pumping light in the first direction. The gain medium receives the pumping light from the first optical component, and generates a first infrared base laser having a first wavelength. The second optical component has a first high transmittance in a first wave band including the first wavelength in the first and the second directions. The Raman crystal receives the first infrared base laser, and generates a second infrared base laser having a second wavelength. The double-harmonic crystal receives the first and the second infrared base lasers, and generates a visible laser light having a third wavelength.