Laser Reflector Research Articles

Innovative methods for trackability and identification improvement of small objects for space traffic management

Technology solutions and operational implications need a evaluation for their crucial role in tracking and identification methodologies. The growth of objects in Earth orbit have made it more important that every space system can be accounted for to be able manage the collision risk between all space objects. Tracking and identification are intimately related as enhanced tracking capabilities minimizes the need for special identification techniques. For both features, the difference between active and passive systems are discussed. Tracking is primarily optical or radar; which of these that is being used drives the most operationally-relevant identification solutions. For example, radar tags can be made to be respond to the radio frequency (RF) energy from the radar and laser reflectors can be completely passive. Whereas identification aids for use by optical tracking are active light sources (of some selected frequency) requiring a power source.

Singular transmission properties of electromagnetic waves in one-dimensional [formula omitted]-symmetric triangular optical waveguide networks

In this paper, the singular transmission properties of electromagnetic waves in one-dimensional PT-symmetric triangular finite periodic optical waveguide networks are investigated. We find that the transmission properties of electromagnetic waves differ significantly depending on whether the imaginary part of the system’s Bloch phase is zero or non-zero. Based on this, the generalized passbands and bandgaps of the PT-symmetric optical waveguide network are defined, and its generalized band structure is presented. Furthermore, we discover that electromagnetic waves incident within the frequency range of generalized bandgaps, where transmittance approaches zero, exhibit a reciprocal relationship between left and right reflectance. The system can generate interesting phenomena such as bidirectional total reflection, unidirectional super reflection, and unidirectional no reflection at these frequencies. It is also demonstrated that the frequency positions of these phenomena can be flexibly controlled by adjusting the length of the PT-symmetric waveguide and the imaginary part of its refractive index. These research findings offer a scientific basis for developing highly sensitive and multifunctional optical filters and laser reflectors.

Hybrid integrated tunable external cavity laser with sub-10 Hz intrinsic linewidth

In this work, a hybrid integrated tunable external cavity laser (ECL) with a sub-10 Hz intrinsic linewidth is demonstrated. In this hybrid ECL, two Si3N4-based subwavelength hole defect assisted microring resonators, acting as high-Q laser reflectors, are butt-coupled with a chip-scale semiconductor optical amplifier at the two edges, respectively. The experimental results show that the hybrid ECL achieves a sub-10 Hz intrinsic linewidth across a wavelength tuning range from 1525 to 1565 nm, featuring a record lowest value of 6.06 Hz. The demonstrated hybrid ECL opens up opportunities toward the applications of high-speed optical communications and high-resolution light detection and ranging.

Accuracy Improvement of a Compact 85Rb Atom Gravimeter by Suppressing Laser Crosstalk and Light Shift

We design and implement a compact 85Rb atom gravimeter (AG). The diameter of the sensor head is 35 cm and the height is 65 cm; the optical and electronic systems are installed in four standard 3U cabinets. The measurement accuracy of this AG is improved by suppress laser crosstalk and light shift. In addition, the angle of the Raman laser reflector is adjusted and locked, and the attitude of the sensing head is automatically adjusted, and the vibration noise is also compensated. The comparison measurement results between this AG and the superconducting gravimeter indicate that its long-term stability is 0.65 μGal @50000 s.

Development of active laser reflector for alignment and monitoring of large-scale scientific devices

As large-scale scientific devices like particle accelerators and tokamaks become bigger and more complex, efficient measurements are needed for these devices. At present, when laser trackers are used to measure these devices, manually rotating reflectors is needed in many circumstances, but it's inefficient and it's inappropriate to be used in the areas where human can't approach. To solve the problem, we designed an active laser reflector, which can rotate to a target angle position controlled by a host computer software. We designed a fixture to embed and clamp a spherically mounted retro-reflector (SMR). And two custom-designed motors are used to drive the SMR to rotate horizontally and vertically respectively. The shaft of the motor has a flange to match another flange on the load, which can reduce the coaxiality error between them. The motor control system consists of two motor controllers and a host computer software, and they communicate through WIFI. We made a prototype of the active laser reflector based on the design scheme and measured the offset of the SMR center, which is around ±0.23 mm. The active laser reflector we designed can increase the measuring and monitoring efficiency for large-scale scientific devices.

Validating Precise Orbit Determination from Satellite-Borne GPS Data of Haiyang-2D

Haiyang-2D (HY-2D) is the fourth satellite in the marine dynamic satellite series established by China. It was successfully launched on 19 May 2021, marking the era of the 3-satellite network in the marine dynamic environment satellite series of China. The satellite’s precision orbit determination (POD) and validations are of great significance for ocean warning and marine altimetry missions. HY-2D is equipped with a laser reflector array (LRA), a satellite-borne Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) receiver, and a satellite-borne dual-frequency GPS receiver named HY2 that was independently developed in China. In this paper, the quality of GPS data collected by the HY2 is analyzed based on indicators such as the multipath effect, cycle slips, and data completeness. The results suggest that the receiver can be used in POD missions involving low-Earth-orbit (LEO) satellites. The precise orbits of HY-2D are determined by the reduced-dynamics (RD) method. Apart from POD, validation of orbit accuracy is another important task for LEO POD. Therefore, two external validation methods are proposed, including carrier differential validation using one GPS satellite and inter-satellite differential validation using two GPS satellites. These are based on space-borne carrier-phase data, and the GPS satellites used for POD validation do not participate in orbit determination. The results of SLR range validation cannot illustrate the orbit accuracy in x, y, and z directions particularly, so to make validation results more intuitive, the SLR three-dimensional (3D) validation is proposed based on SLR range validation, and the RMSs in x, y, and z directions are 2.66, 3.32, and 2.69 cm, respectively. The results of SLR 3D validation are the same as those of SLR range validation, which proves that the new external validation method provided by SLR 3D is reliable. The RMSs of carrier differential validation and inter-satellite differential validation are 0.68 and 1.06 cm, respectively. The proposed validation methods are proved to be reliable.

An autonomous lunar geophysical experiment package (ALGEP) for future space missions

Geophysical observations will provide key information about the inner structure of the planets and satellites and understanding the internal structure is a strong constraint on the bulk composition and thermal evolution of these bodies. Thus, geophysical observations are a key to uncovering the origin and evolution of the Moon. In this article, we propose the development of an autonomous lunar geophysical experiment package, composed of a suite of instruments and a central station with standardized interface, which can be installed on various future lunar missions. By fixing the interface between instruments and the central station, it would be possible to easily configure an appropriate experiment package for different missions. We describe here a series of geophysical instruments that may be included as part of the geophysical package: a seismometer, a magnetometer, a heat flow probe, and a laser reflector. These instruments will provide mechanical, thermal, and geodetic parameters of the Moon that are strongly related to the internal structure. We discuss the functionality required for future geophysical observations of the Moon, including the development of the central station that will be used commonly by different payloads.

Integrated Coherent Tunable Laser (ICTL) With Ultra-Wideband Wavelength Tuning and Sub-100 Hz Lorentzian Linewidth

This paper describes the design, fabrication, and record performance of a new class of ultra-wideband wavelength tuning, ultra-low noise semiconductor laser, the Integrated Coherent Tunable Laser (ICTL). The ICTL device is designed for, and fabricated in, a CMOS foundry based Silicon Photonics platform, utilizing heterogeneous integration of III-V material to create the integrated gain section of the laser–enabling high-volume mass-market manufacturing at low cost and with high reliability. The ICTL incorporates three or more ultra-low loss micro-ring resonators, with large ring size, in a Sagnac loop reflector geometry, creating exceptional laser reflector performance, plus an extended laser cavity length that enables highly-coherent output; ultra-low linewidth and phase noise. This paper describes record integrated laser performance; 118 nm wavelength tuning, covering S-, C- and L-bands, with Lorentzian linewidth <100 Hz, and with excellent relative intensity noise (RIN) of ≤ −155 dBc/Hz. The remarkable performance of the ICTL device, coupled with the high volume/low cost capability of the Silicon Photonics platform enables next-generation applications including ultra-wideband WDM transmission systems, fiber-optic and medical-wearable sensing systems, and automotive FMCW LiDAR systems utilizing wavelength scanning.

Laser Actuated Non-Invasive Smart Instrumentation - Enabling Lab-on-Chip

Non-invasive optical instrumentation provides non-destructive, reliable, and precise control in industrial process regulation, especially when chemical compounds or organic material surfaces are always a point of care. Nanomaterial dynamics intrinsically exhibit higher order of visual scanning complexities, associate wholly or partially to the poor scanning instrumentations. Additionally, growing trends in analytical instrumentation towards smart Lab-On-a-Chip (IoT sensing nodes) have shifted the emphasis on sensitivity and robustness tailoring Product Specific Environment (PSE). This work presents a hybrid laser actuated scanning mechanism, rastered back and forth 3-D imaging technique enabling Microscopy to its widest application in biological and material sciences and hence rose challenge of predicting large missing or incorrect data obtained during experiments. Our Confocal Self Calibrated Interferometry based fabricated Laser Sensor demonstrates its efficacy in non-invasive scanning microscopy to achieve a high-resolution 3D topographical view, eventually an add-on to the analytical model of microorganisms and nanomaterial. In contrast to linear controllers, PI controllers demonstrate better stability in controlling the laser leakage at tip, which consists of two channel tube adjustments and successively in laser reflector lens, Photo Multiplier Tube (PMT), and Data Acquisition Unit (DAU). We expose our results for error propagation across various grid patterns over a 1mm² section, plotting the intensity of a key band or bands over the PMT grid. We observe that the instrumentation errors can be nullified by modeling the ergodicity of information flow along with the SLM instrumentation.

Characterization in Dynamic Load Environment of COTS Synthetic Sapphire Bearings for Application in Magnetic Suspension in Space

The present research investigates the application of a cardan suspension making use of permanent magnet (PM) bearings employed to obtain high reliable/low-cost solutions for the permanent alignment of directional payloads such as laser reflectors for the Next Generation Lunar Retroreflector (NGLR) experiment or antennas to be deployed on the moon’s surface. According to Earnshaw’s Theorem, it is not possible to fully stabilize an object using only a stationary magnetic field. It is also necessary to provide axial control of the shaft since the PM bearings support the radial load but, they produce an unstable axial force when losing alignment between the stator and rotor magnets stack. In this work, the use of commercial off-the-shelf (COTS) sapphire as axial bearings in the cardan suspension has been investigated by testing their behavior in response to some of the dynamic loads experienced during the qualification tests for space missions. The work is innovative in the sense that COTS sapphire assembly has never been investigated for space mission qualification. As Artemis mission loads have not been yet provided for NGLR, test loads for this study are those used for the proto-qualification of the INFN INRRI payload for the ESA ExoMars EDM mission. Tests showed that, along the x and y directions, no damages were produced on the sapphire, while, unfortunately, on the z direction both sapphires were badly damaged at nominal loads.

A High-Resolution Microfluidic LAPS Imaging System for 3D Cell Metabolism Monitoring

A High-Resolution Microfluidic LAPS Imaging System for 3D Cell Metabolism Monitoring

Study of the dependence of the spatial structure of the optical response of a microsatellite on its speed and orbit height

The paper considers the problem of optical radiation propagation in a passive laser reflector satellite orbiting the Earth, along with reflected signal formation at the earth surface. In these conditions, the optical system will be significantly affected by moving media optics, which may interfere with the possibility of receiving the signal reflected by the satellite. The paper aims to develop a mathematical simulation taking into account the effects of moving media optics and track the spatiotemporal structure of the signal as a function of the optical system velocity.

Investigation on the effects of laser heating on surface quality of OFHC copper in diamond cutting process

Due to the excellent electric and thermal conductivity leading to a high laser damage threshold, oxygen-free high conductivity (OFHC) copper is an ideal material for fabricating high power laser reflectors. However, in diamond machining of OFHC copper, the surface quality deteriorates dramatically with the increasing depth of cut resulting from the formation of surface delamination defects. The formation of these defects is suspected of being influenced by the ductility of OFHC copper, which is temperature dependent. In this research, laser heating was introduced into the diamond cutting process to investigate the influence of temperature on the formation of surface defects of OFHC copper. It was found that laser heating was beneficial to the improvement of the surface quality of OFHC copper at large depth of cut in diamond cutting process.

The Ginninderra CH4 and CO2 release experiment: An evaluation of gas detection and quantification techniques

A methane (CH4) and carbon dioxide (CO2) release experiment was held from April to June 2015 at the Ginninderra Controlled Release Facility in Canberra, Australia. The experiment provided an opportunity to compare different emission quantification techniques against a simulated CH4 and CO2 point source release, where the actual release rates were unknown to the participants. Eight quantification techniques were assessed: three tracer ratio techniques (two mobile); backwards Lagrangian stochastic modelling; forwards Lagrangian stochastic modelling; Lagrangian stochastic (LS) footprint modelling; atmospheric tomography using point and using integrated line sensors. The majority of CH4 estimates were within 20% of the actual CH4 release rate (5.8 g/min), with the tracer ratio technique providing the closest estimate to both the CH4 and CO2 release rates (100 g/min). Once the release rate was known, the majority of revised estimates were within 10% of the actual release rate. The study illustrates the power of measuring the emission rate using multiple simultaneous methods and obtaining an ensemble median or mean. An ensemble approach to estimating the CH4 emission rate proved successful with the ensemble median estimate within 16% for the actual release rate for the blind release experiment and within 2% once the release rate was known. The release also provided an opportunity to assess the effectiveness of stationary and mobile ground and aerial CH4 detection technologies. Sensor detection limits and sampling rates were found to be significant limitations for CH4 and CO2 detection. A hyperspectral imager’s capacity to image the CH4 release from 100 m, and a Boreal CH4 laser sensor’s ability to track moving targets suggest the future possibility to map gas plumes using a single laser and mobile aerial reflector.

试验卫星激光反射器的设计和试验

试验卫星激光反射器的设计和试验

Design of laser retro-reflectors and experiment of laser ranging for PN1B satellite

PN1Bexperimental satellite is an initiative project of China aiming at thermosphere density detection, which has been successfully launched into outer space from Taiyuan Satellite Launch Center in September, 2015. In order to satisfy the inspection standard and high precision measurement application requirements for the satellite GPS orbit determination data, and according to fact that the satellite could not provide the required installation area for the array structure of laser reflectors, PN1B satellite is equipped with multiple small (10 mm) cube prisms for satellite laser ranging. After sending the satellite into orbit, the TROS1000 mobile satellite laser ranging system was used for the tracking and laser ranging experiments. The measurement results show that the laser echo data are enough, the average number of photons per second laser echo is as high as 173, marking such small laser reflectors as the cube prisms will play an important role in the application of precise orbit determination.

1m급 인공위성 레이저추적 시스템용 고속·고정밀 추적마운트 개발 및 예비 성능분석

본 연구에서는 국내 최초 개발 예정인 1m급 인공위성 레이저추적 시스템(Satellite Laser Ranging, SLR)의 추적마운트 (Tracking Mount) 모듈 개발을 위한 예비설계 및 성능분석 결과를 제시한다. 인공위성 레이저추적 시스템은 위성까지의 거리를 정밀하게 측정하는 시스템으로 지상의 관측소에서 반사경을 탑재하고 있는 인공위성까지 레이저를 발사하여 되돌아오는 레이저 사이의 시간간격을 측정하는 시스템으로서, 현존하는 인공위성까지의 거리측정 시스템 중 가장 정밀한 측정 시스템이다. 본 논문에서 제안하는 인공위성 레이저 추적 시스템용 고속 고정밀 추적마운트의 추적범위는 고도 300 km에서 정지궤도(고도 36,000 km)까지 가능하며, 레이저 반사경을 탑재한 인공위성에 대해 주 야간 레이저추적이 가능해야 한다. 이러한 요구사항을 만족하기 위해, 본 연구에서는 고속 고정밀 추적마운트 기구부 설계 및 구조해석을 수행하였고, 추적마운트의 원활한 제어를 위한 모션 제어 시스템을 설계하여 예비 성능 분석을 실시한 결과를 소개하였다. This paper presents preliminary design and performance analysis of a fast and high precision Tracking Mount for 1m Satellite Laser Ranging(SLR) which is development by Korea Astronomy and Space science Institute(KASI). SLR is considered to be the most accurate technique currently available for the precise orbit determination of Earth satellites. The SLR technique measures the time of flight between pulses emitted from laser transmitter and pulses returned from satellites with laser retro-reflector array. It provides millimeter level precision of range measurements between SLR stations and satellites. A fast and high precision Tracking Mount for SLR which is proposed in this research should be capable of day and nighttime laser tracking about the satellites with laser reflectors from 200 km to 36,000 km altitude(geosynchronous orbit). In order to meet this requirement, we performed mechanical design and structural analysis for Tracking Mount. Also we designed the motion control system and conducted pre-performance analysis to obtain good performance results for a fast and high precision Tracking Mount.

Studies on Nanostructure Aluminium Thin Film Coatings Deposited using DC magnetron Sputtering Process

Nanostructured thin film metallic coatings has become an area of intense research particularly in applications related solar, sensor technologies and many other optical applications such as laser windows, mirrors and reflectors. Thin film metallic coatings were deposited using DC magnetron sputtering process. The deposition rate was varied to study its influence on optical behavior of Aluminum thin films at a different argon flow rate. Studies on the optical response of these nanostructure thin film coatings were characterized using UV-VIS-NIR spectrophotometer with integrating sphere in the wavelength range of (250-2500nm) and Surface morphology were carried out using atomic force microscope with roughness ranging from 2 to 20nm and thickness was measured using Dektak measuring instrument. The reflection behavior of aluminium coatings on polycarbonate substrates has been evaluated. UV-VIS-NIR Spectrophotometer analysis indicates higher reflectance of 96% for all the films in the wavelength range of 250 nm to 2500 nm. Nano indentation study revealed that there was a considerable change in hardness values of the films prepared at different conditions.

Electron heating in radiation-pressure-driven proton acceleration with a circularly polarized laser.

Dynamics of electron heating in the radiation-pressure-driven acceleration through self-induced transparency (SIT) is investigated with the help of particle-in-cell simulations. The SIT is achieved through laser filamentation which is seeded by the transverse density modulations due to the Rayleigh-Taylor-like instability. We observe stronger SIT induced electron heating for the longer duration laser pulses leading to deterioration of accelerated ion beam quality (mainly energy spread). Such heating can be controlled to obtain a quasimonoenergetic beam by cascaded foils targets where a second foil behind the main accelerating foil acts as a laser reflector to suppress the SIT.

イオンビームによる月面設置用コーナーキューブミラーの精密加工

イオンビームによる月面設置用コーナーキューブミラーの精密加工