An apparatus for spectral broadening of laser pulses includes a main body, a plurality of mirror elements fastened to the main body, each having a mirror surface formed thereon and configured to reflect the laser pulses the plurality of mirror elements being fastened to a main body, and at least one nonlinear optical medium for the passage of the laser pulses for the generation of a nonlinear phase (Φ.sub.NL) by self-phase modulation. The at least one nonlinear optical medium may be a sheet-like and disk-shaped solid-state optical medium and/or a gaseous optical medium.

Object: To provide a remote substance identification device that can identify an unidentified substance, such as a harmful substance, from a remote location. Solution: Provided are a remote substance identification device and method, the device comprising a laser device 10 that emits a laser beam to an irradiated space; a wavelength conversion device 20 that converts a wavelength of the laser beam emitted from the laser device into a plurality of different wavelengths and that emits laser beams of the different wavelengths to the irradiated space; a light collecting-detecting device 30, 40, 50 that collects and detects resonance Raman-scattered light generated from an irradiated object due to resonance Raman scattering; and a processor 60 that identifies the irradiated object on the basis of a result detected by the collecting-detecting device 30, 40, 50.

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.

This invention provides a pulse shaping technique that can yield a pulsed laser having a smaller energy fluctuation than that of a conventional pulse shaping technique using one or two non-linear optical crystals. A pulse shaping device includes: a non-linear optical crystal group including at least three non-linear optical crystals arranged side by side on an optical path of an input pulsed laser.

A photonic integrated circuit (PIC) includes a first microresonator that generates a two-mode squeezed vacuum using spontaneous four-wave mixing. Specifically, the first microresonator uses a nonlinear optical medium to convert two pump photons into a pair of entangled signal and idler photons. Due to imperfect conversion efficiency, some of the pump light may co-propagate with the signal light and idler light. To remove this “unconverted” pump light, the PIC includes a second microresonator that is tuned to resonate with only the pump light. The second microresonator is located after the first microresonator and couples the unconverted pump light into a waveguide that guide the light off the PIC. Thus, the second microresonator acts as a notch filter. Integrating this pump filter onto the PIC adds negligibly to the path length of the squeezed light, and therefore saves the propagation losses incurred when using a much larger off-chip filter.

A Faraday rotator and an optical isolator having a high transmittance and a high Verdet constant are provided. The optical isolator includes at least a Faraday rotator that rotates a polarization plane of incident light in a non-reciprocal manner, a polarizer disposed on a light incident side of the Faraday rotator, and an analyzer disposed on a light exit side of the Faraday rotator. The Faraday rotator is made of an oxide containing ytterbium oxide (Yb.sub.2O.sub.3), and is manufactured by a ceramic manufacturing process, wherein the oxide is allowed to contain an oxide of a metal other than ytterbium, and the proportion of ytterbium in all metal atoms in the oxide is 80% or more.

An optical system for increasing contrast of pulsed laser radiation includes a first polarization setting optical unit for setting an elliptical polarization state of the pulsed laser radiation, and a multipass cell having at least two opposing mirrors. The pulsed laser radiation passes the multipass cell with formation of a plurality of intermediate focus zones. The multipass cell is filled with a gas having an optical nonlinearity that causes an intensity-dependent rotation of an alignment of the elliptical polarization state of the pulsed laser radiation, such that the multipass cell outputs beam portions having differently aligned elliptical polarization states on account of the intensity-dependent rotation. The optical system further includes an optical beam splitting system for splitting the beam portions having differently aligned elliptical polarization states.

An integrated optical circuit for an optical neural network is provided. The integrated optical circuit is configured to process a phase-encoded optical input signal and to provide a phase-encoded output signal depending on the phase-encoded optical input signal. The phase-encoded output signal emulates a synapse functionality with respect to the phase-encoded optical input signal. A related method and a related design structure are further provided.

An entanglement-enhanced interferometry system includes a source of correlated photons configured to two-mode squeezed vacuum (TMSV), a polarizing splitter or off-axis polarizing coupler configured to separate the correlated photons into two paths, a polarization control device configured to rotate polarization of photons on one of the two paths relative to the photons on the other of the two paths in order to make photons indistinguishable, a coupler configured to entangle the indistinguishable photons, and a polarization maintaining fiber-based interferometer configured to use the entangled photons as the input state. The source of correlated photons might be a nonlinear element such as a periodically poled element such as a lithium niobate bulk crystal or waveguide. The interferometer might be a Mach-Zehnder or a common path configuration. The coupler might be a 50:50 coupler or a polarizing coupler 45 degrees off-axis.

A light modulator includes a base layer, a metal reflective layer formed on the base layer, a modulation layer of a nonlinear optical crystal formed on the reflective layer, and a conductive pattern layer including a plurality of pattern portions arranged periodically in a first direction and each extending in a second direction, and formed on the modulation layer. The modulation layer changes a reflectance for object light by changing a refractive index when a voltage is applied between the reflective layer and the conductive pattern layer. The light modulator outputs the object light being incident from an upper surface side of the modulation layer, transmitted through the modulation layer, and reflected by the reflective layer to the outside as modulated light with an intensity modulated by the reflectance change.