The Lobster Eye Imager for Astronomy(LEIA),a pathfinder of the Wide-field X-ray Telescope of the Einstein Probe mission,was successfully launched onboard the SATech-01 satellite of the Chinese Academy of Sciences on20...The Lobster Eye Imager for Astronomy(LEIA),a pathfinder of the Wide-field X-ray Telescope of the Einstein Probe mission,was successfully launched onboard the SATech-01 satellite of the Chinese Academy of Sciences on2022 July 27.In this paper,we introduce the design and on-ground test results of the LEIA instrument.Using stateof-the-art Micro-Pore Optics(MPO),a wide field of view of 346 square degrees(18.6°×18.6°)of the X-ray imager is realized.An optical assembly composed of 36 MPO chips is used to focus incident X-ray photons,and four large-format complementary metal-oxide semiconductor(CMOS)sensors,each of size 6 cm×6 cm,are used as the focal plane detectors.The instrument has an angular resolution of 4’-8’(in terms of FWHM)for the central focal spot of the point-spread function,and an effective area of 2-3 cm^(2) at 1 keV in essentially all the directions within the field of view.The detection passband is 0.5-4 keV in soft X-rays and the sensitivity is2-3×10^(-11) erg s^(-1) cm^(-2)(about 1 milliCrab)with a 1000 s observation.The total weight of LEIA is 56 kg and the power is 85 W.The satellite,with a design lifetime of 2 yr,operates in a Sun-synchronous orbit of 500 km with an orbital period of 95 minutes.LEIA is paving the way for future missions by verifying in flight the technologies of both novel focusing imaging optics and CMOS sensors for X-ray observation,and by optimizing the working setups of the instrumental parameters.In addition,LEIA is able to carry out scientific observations to find new transients and to monitor known sources in the soft X-ray band,albeit with limited useful observing time available.展开更多
The effect of spatial hole burning(SHB)on dual-wavelength self-mode-locked lasers based on physically combined Nd:YVO_(4)∕Nd:LuVO_(4)and Nd:YVO_(4)∕Nd:KGW composite active medium is comparatively investigated.The le...The effect of spatial hole burning(SHB)on dual-wavelength self-mode-locked lasers based on physically combined Nd:YVO_(4)∕Nd:LuVO_(4)and Nd:YVO_(4)∕Nd:KGW composite active medium is comparatively investigated.The length of the first Nd:YVO_(4)crystal is optimized to realize a highly compact and efficient TEM00-mode picosecond laser at 1.06μm with optical conversion efficiency greater than 20%.When the SHB effect is enhanced by decreasing the separation between the input end mirror and the composite gain medium,it is experimentally found that not only the pulse duration monotonically decreases,but also the temporal behavior gradually displays a narrow-peak-on-a-pedestal shape for the Nd:YVO_(4)∕Nd:LuVO_(4)scheme,while the multipulse operation can be obtained for the Nd:YVO_(4)∕Nd:KGW configuration.These phenomena are further explored by numerically simulating mode-locked pulses from the experimentally measured optical spectra.展开更多
The study of structured laser beams has been one of the most active fields of research for decades, particularly in exploring laser beams with orbital angular momentum. The direct generation of structured beams from l...The study of structured laser beams has been one of the most active fields of research for decades, particularly in exploring laser beams with orbital angular momentum. The direct generation of structured beams from laser resonators is deeply associated with the formation of transverse modes. The wave representations of transverse modes of spherical cavities are usually categorized into Hermite–Gaussian(HG) and Laguerre–Gaussian(LG)modes for a long time. Enormous experimental results have revealed that the generalized representation for the transverse modes is the Hermite–LG(HLG) modes. We make a detailed overview for the theoretical description of the HLG modes from the representation of the spectral unitary group of order 2 in the Jordan–Schwinger map.Furthermore, we overview how to derive the integral formula for the elliptical modes based on the Gaussian wave-packet state and the inverse Fourier transform. The relationship between the HLG modes and elliptical modes is linked by the quantum Fourier transform. The most striking result is that the HLG modes can be exactly derived as the superposition of the elliptical modes without involving Hermite and Laguerre polynomials.Finally, we discuss the application of the HLG modes in characterizing the propagation evolution of the vortex structures of HG beams transformed by an astigmatic mode converter. This overview certainly provides not only a novel formula for transverse modes, but also a pedagogical insight into quantum physics.展开更多
A graphene-coated microfiber(GCM)-based hybrid waveguide structure formed by wrapping monolayer graphene around a microfiber with length of several millimeters is pumped by a nanosecond laser at ~1550 nm, and multiord...A graphene-coated microfiber(GCM)-based hybrid waveguide structure formed by wrapping monolayer graphene around a microfiber with length of several millimeters is pumped by a nanosecond laser at ~1550 nm, and multiorder cascaded four-wave-mixing(FWM) is effectively generated. By optimizing both the detuning and the pump power, such a GCM device with high nonlinearity and compact size would have potential for a wide range of FWM applications, such as phase-sensitive amplification, multi-wavelength filter, all-optical regeneration and frequency conversion, and so on.展开更多
基金supported by the Einstein Probe project,a mission in the Strategic Priority Program on Space Science of CAS(grant Nos.XDA15310000,XDA15052100)in part been supported by the European Union’s Horizon 2020 Program under the AHEAD2020 project(grant No.871158).
文摘The Lobster Eye Imager for Astronomy(LEIA),a pathfinder of the Wide-field X-ray Telescope of the Einstein Probe mission,was successfully launched onboard the SATech-01 satellite of the Chinese Academy of Sciences on2022 July 27.In this paper,we introduce the design and on-ground test results of the LEIA instrument.Using stateof-the-art Micro-Pore Optics(MPO),a wide field of view of 346 square degrees(18.6°×18.6°)of the X-ray imager is realized.An optical assembly composed of 36 MPO chips is used to focus incident X-ray photons,and four large-format complementary metal-oxide semiconductor(CMOS)sensors,each of size 6 cm×6 cm,are used as the focal plane detectors.The instrument has an angular resolution of 4’-8’(in terms of FWHM)for the central focal spot of the point-spread function,and an effective area of 2-3 cm^(2) at 1 keV in essentially all the directions within the field of view.The detection passband is 0.5-4 keV in soft X-rays and the sensitivity is2-3×10^(-11) erg s^(-1) cm^(-2)(about 1 milliCrab)with a 1000 s observation.The total weight of LEIA is 56 kg and the power is 85 W.The satellite,with a design lifetime of 2 yr,operates in a Sun-synchronous orbit of 500 km with an orbital period of 95 minutes.LEIA is paving the way for future missions by verifying in flight the technologies of both novel focusing imaging optics and CMOS sensors for X-ray observation,and by optimizing the working setups of the instrumental parameters.In addition,LEIA is able to carry out scientific observations to find new transients and to monitor known sources in the soft X-ray band,albeit with limited useful observing time available.
基金National Science Council for financial support of this research under Contract No.NSC-100-2628-M-009-001-MY3.
文摘The effect of spatial hole burning(SHB)on dual-wavelength self-mode-locked lasers based on physically combined Nd:YVO_(4)∕Nd:LuVO_(4)and Nd:YVO_(4)∕Nd:KGW composite active medium is comparatively investigated.The length of the first Nd:YVO_(4)crystal is optimized to realize a highly compact and efficient TEM00-mode picosecond laser at 1.06μm with optical conversion efficiency greater than 20%.When the SHB effect is enhanced by decreasing the separation between the input end mirror and the composite gain medium,it is experimentally found that not only the pulse duration monotonically decreases,but also the temporal behavior gradually displays a narrow-peak-on-a-pedestal shape for the Nd:YVO_(4)∕Nd:LuVO_(4)scheme,while the multipulse operation can be obtained for the Nd:YVO_(4)∕Nd:KGW configuration.These phenomena are further explored by numerically simulating mode-locked pulses from the experimentally measured optical spectra.
基金supported by the Ministry of Science and Technology of Taiwan (Contract No. 108-2119-M-009-005)。
文摘The study of structured laser beams has been one of the most active fields of research for decades, particularly in exploring laser beams with orbital angular momentum. The direct generation of structured beams from laser resonators is deeply associated with the formation of transverse modes. The wave representations of transverse modes of spherical cavities are usually categorized into Hermite–Gaussian(HG) and Laguerre–Gaussian(LG)modes for a long time. Enormous experimental results have revealed that the generalized representation for the transverse modes is the Hermite–LG(HLG) modes. We make a detailed overview for the theoretical description of the HLG modes from the representation of the spectral unitary group of order 2 in the Jordan–Schwinger map.Furthermore, we overview how to derive the integral formula for the elliptical modes based on the Gaussian wave-packet state and the inverse Fourier transform. The relationship between the HLG modes and elliptical modes is linked by the quantum Fourier transform. The most striking result is that the HLG modes can be exactly derived as the superposition of the elliptical modes without involving Hermite and Laguerre polynomials.Finally, we discuss the application of the HLG modes in characterizing the propagation evolution of the vortex structures of HG beams transformed by an astigmatic mode converter. This overview certainly provides not only a novel formula for transverse modes, but also a pedagogical insight into quantum physics.
基金supported by National Natural Science Foundation of China under Grants 61290312, 61107072, 61107073, and 61475032supported by Program for Changjiang Scholars and Innovative Research Team in Universities of China (PCSIRT)the “111 Project” of China Education Ministry
文摘A graphene-coated microfiber(GCM)-based hybrid waveguide structure formed by wrapping monolayer graphene around a microfiber with length of several millimeters is pumped by a nanosecond laser at ~1550 nm, and multiorder cascaded four-wave-mixing(FWM) is effectively generated. By optimizing both the detuning and the pump power, such a GCM device with high nonlinearity and compact size would have potential for a wide range of FWM applications, such as phase-sensitive amplification, multi-wavelength filter, all-optical regeneration and frequency conversion, and so on.
