Abstract: A smart flashlight control method and a mobile terminal are provided. The method includes: when detecting that a photographing mode of a mobile terminal is turned on, detecting ambient light intensity of the mobile terminal; when the ambient light intensity of the mobile terminal is smaller than a first threshold, turning on a flashlight; detecting whether a target to be photographed by the mobile terminal includes a predetermined type; and when the target to be photographed includes the predetermined type, adjusting light intensity of a fill light in the mobile terminal, to achieve the best photographing effect.

Abstract: A smart flashlight control method and a mobile terminal are provided. The method includes: when detecting that a photographing mode of a mobile terminal is turned on, detecting ambient light intensity of the mobile terminal; when the ambient light intensity of the mobile terminal is smaller than a first threshold, turning on a flashlight; detecting whether a target to be photographed by the mobile terminal includes a predetermined type; and when the target to be photographed includes the predetermined type, adjusting light intensity of a fill light in the mobile terminal, to achieve the best photographing effect.

Abstract: The present application discloses a nonlinear optical crystal material, preparation method and application of the nonlinear optical crystal material. A nonlinear optical crystal material, whose molecular formula is Ga2Se3; wherein the crystal structure of said nonlinear optical crystal material belongs to trigonal system, space group R3 with the lattice parameters of a=b=3˜4.2 ?, c=9˜10 ?, ?=?=90°, ?=120° and Z=1. The nonlinear optical crystal material has an excellent infrared nonlinear optical performance, whose frequency-doubling intensity can reach 9.3 times of AgGaS2 with the same particle size, and it meets type-I phase matching; and its laser damage threshold can reach 7.5 times of AgGaS2 with the same particle size. The nonlinear optical crystal material has important application value in the frequency-converters which can be used for frequency doubling, sum frequency, difference frequency, optical parametric oscillation of laser in mid and far infrared waveband, and the like.

Abstract: The present application discloses a nonlinear optical crystal material, preparation method and application of the nonlinear optical crystal material. The nonlinear optical crystal material has an excellent infrared nonlinear optical performance, whose frequency-doubling intensity can reach 9.3 times of AgGaS2 with the same particle size, and it meets type-I phase matching; and its laser damage threshold can reach 7.5 times of AgGaS2 with the same particle size. The nonlinear optical crystal material has important application value in the frequency-converters which can be used for frequency doubling, sum frequency, difference frequency, optical parametric oscillation of laser in mid and far infrared waveband, and the like.

Abstract: The present application discloses a nonlinear optical crystal material, preparation method and application of the nonlinear optical crystal material. The nonlinear optical crystal material has an excellent infrared nonlinear optical performance, whose frequency-doubling intensity can reach 9.3 times of AgGaS2 with the same particle size, and it meets type-I phase matching; and its laser damage threshold can reach 7.5 times of AgGaS2 with the same particle size. The nonlinear optical crystal material has important application value in the frequency-converters which can be used for frequency doubling, sum frequency, difference frequency, optical parametric oscillation of laser in mid and far infrared waveband, and the like.

Abstract: This disclosure provides an optical parametric oscillator, comprising, in a light path, a first lens, a laser crystal, a second lens, a nonlinear optical crystal, and a third lens in this order, wherein an optical parametric oscillation chamber is formed between the second lens and the third lens, and the nonlinear optical crystal is a monoclinic Ga2S3 crystal, the space group of the monoclinic Ga2S3 crystal is Cc, and the unit cell parameters are a=11.1 ?, b=6.4 ?, c=7.0 ?, ?=90°, ?=121°, ?=90°, and Z=4.

Abstract: This disclosure provides a second harmonic generator and an optical parametric oscillator, the second harmonic generator and the optical parametric oscillator comprise one or more nonlinear optical frequency conversion crystal and a pump laser source, the nonlinear optical frequency conversion crystal is a monoclinic Ga2S3 crystal, the space group of the monoclinic Ga2S3 crystal is Cc, and the unit cell parameters are a=11.1 ?, b=6.4 ?, c=7.0 ?, ?=90°,?=121°, ?=90°, and Z=4.

Abstract: This disclosure provides a second harmonic generator and an optical parametric oscillator, the second harmonic generator and the optical parametric oscillator comprise one or more nonlinear optical frequency conversion crystal and a pump laser source, the nonlinear optical frequency conversion crystal is a monoclinic Ga.sub.2S.sub.3 crystal, the space group of the monoclinic Ga.sub.2S.sub.3 crystal is Cc, and the unit cell parameters are a=11.1.ANG., b=6.4.ANG., c=7.0.ANG., .alpha.=90.degree., .beta.=121.degree., .gamma.=90.degree., and Z=4.

Abstract: This disclosure provides a second harmonic generator and an optical parametric oscillator, the second harmonic generator and the optical parametric oscillator comprise one or more nonlinear optical frequency conversion crystal and a pump laser source, the nonlinear optical frequency conversion crystal is a monoclinic Ga2S3 crystal, the space group of the monoclinic Ga2S3 crystal is Cc, and the unit cell parameters are a=11.1 ?, b=6.4 ?, c=7.0 ?, ?=90°, ?=121°, ?=90°, and Z=4.