Provided are a high-energy and high-powered laser light source and a photoemission electron microscope using the laser light source. The laser light source 2 is intended for use in the photoemission electron microscope for emitting a quasi-continuous wave laser 7 and includes: a first laser light source 100 configured to emit a continuous wave coherent light 100a, an optical resonator 110 including an optical path in which the continuous wave coherent light 100a circulates and including a non-linear optical element 114 disposed on the optical path, and a quasi-continuous wave light source 120 configured to emit a quasi-continuous wave coherent light 120a having a wavelength shorter than that of the continuous wave coherent light 100a and having a near rectangular output waveform. When the quasi-continuous wave coherent light 120a is incident on the non-linear optical element 114 from outside the optical resonator 110 while the continuous wave coherent light 100a is entering the optical resonator 110 to circulate in the optical path, the quasi-continuous wave laser 7 having a wavelength shorter than that of the quasi-continuous wave coherent light 120a is emitted from the non-linear optical element 114.

A graphene structure includes one or more graphene layers. The graphene layers allow for microwave squeezing with gains up to 24 dB over a wide bandwidth.

A electronic method, includes receiving, by a graphene structure, a microwave signal. The microwave signal has a driving voltage level. The electronic method includes generating, by the graphene structure, optical photons based on the microvolts. The electronic method includes outputting, by the graphene structure, the optical photons.

A electronic method, includes receiving, by a graphene structure, a microwave signal. The microwave signal has a driving voltage level. The electronic method includes generating, by the graphene structure, optical photons based on the microvolts. The electronic method includes outputting, by the graphene structure, the optical photons.

Systems and methods for precision control of microresonator (MR) based frequency combs can implement optimized MR actuators or MR modulators to control long-term locking of carrier envelope offset frequency, repetition rate, or resonance offset frequency of the MR. MR modulators can also be used for amplitude noise control. MR parameters can be locked to external reference frequencies such as a continuous wave laser or a microwave reference. MR parameters can be selected to reduce cross talk between the MR parameters, facilitating long-term locking. The MR can be locked to an external two wavelength delayed self-heterodyne interferometer for low noise microwave generation. An MR-based frequency comb can be tuned by a substantial fraction or more of the free spectral range (FSR) via a feedback control system. Scanning MR frequency combs can be applied to dead-zone free spectroscopy, multi-wavelength LIDAR, high precision optical clocks, or low phase noise microwave sources.

A display apparatus includes a liquid crystal panel, and a light source apparatus configured to irradiate the liquid crystal panel with light. The light source apparatus includes a plurality of light sources configured to emit blue light, and a reflective sheet with a plurality of holes through which the light passes. The plurality of holes includes a first hole disposed at an edge portion of the reflective sheet, and a second hole in which a distance from an edge of the reflective sheet to the second hole is greater than a distance between the edge of the reflective sheet and the first hole and a plurality of first light conversion patches arranged along a circumference of a circle surrounding the first hole on the reflective sheet, and a plurality of second light conversion patches arranged along a circumference of a circle surrounding the second hole on the reflective sheet.

An optical frequency control device includes: a detection circuit to receive first light including a first frequency, receive second light including a second frequency, modulate the first light with a local oscillation signal, and detect a differential beat signal between the frequency of sideband light included in the modulated first light and the second frequency; a light source control circuit to change the second frequency by frequency-dividing the differential beat signal with a first frequency division number, by frequency-dividing a reference signal with a second frequency division number, and by outputting a phase error signal indicating a phase difference between the frequency-divided differential beat signal and the frequency-divided reference signal; and a signal processing unit to set each of the first frequency division number and the second frequency division number according to the set value of a frequency difference between the first frequency and the second frequency.

A display apparatus includes a liquid crystal panel; a plurality of light sources configured to emit blue light; a reflective sheet comprising four edge portions, wherein a plurality of holes are disposed on the reflective sheet, the plurality of holes comprises a first hole and a second hole on each of the four edge portions of the reflective sheet, each of the four edge portions comprises an edge of the reflective sheet, the first hole is disposed at a first distance from the edge of the reflective sheet, and the second hole is disposed at a second distance from the edge of the reflective sheet, wherein the second distance is greater than the first distance; and a plurality of light conversion dots comprising a plurality of first light conversion dots and a plurality of second light conversion dots.

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 display apparatus includes a liquid crystal panel; a plurality of light sources configured to emit blue light; a reflective sheet comprising four edge portions, wherein a plurality of holes are disposed on the reflective sheet, the plurality of holes comprises a first hole and a second hole on each of the four edge portions of the reflective sheet, each of the four edge portions comprises an edge of the reflective sheet, the first hole is disposed at a first distance from the edge of the reflective sheet, and the second hole is disposed at a second distance from the edge of the reflective sheet, wherein the second distance is greater than the first distance; and a plurality of light conversion dots comprising a plurality of first light conversion dots and a plurality of second light conversion dots.