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Showing papers on "Parabolic reflector published in 2017"


Journal ArticleDOI
TL;DR: In this paper, a feasibility study is carried out in order to investigate the description, working principles of the solar parabolic dish systems worldwide, and their potential use in some countries are given.
Abstract: In this paper, a feasibility study is carried out in order to investigate the description, working principles of the solar parabolic dish systems worldwide, and their potential use in some countries are given A study of the system is presented, which able to show the performance of the system and accounting for the main technical aspects of the concentrator, receiver and Stirling engine The study reviews the parabolic solar dish technologies and the design factors adapted in different applications such as material of the reflector concentrators, shape of the reflector concentrators and the receiver, solar radiation at the concentrator, diameter of the parabolic dish concentrator, sizing the aperture area of concentrator, focal length of the parabolic dish, the focal point diameter, sizing the aperture area of receiver, geometric concentration ratio, and rim angle In order to identify the optimum design feasible option for installation of the solar dish plants, the technical characteristics of some implemented solar dishes worldwide are presented The study take into consideration available solar potential and the different designs of solar dishes

96 citations


Journal ArticleDOI
TL;DR: J-KAREN-P approached the physical limits of the beam quality: diffraction limit of the focal spot and bandwidthlimit of the pulse shape, removing the chromatic aberration, angular chirp, wavefront and spectral phase distortions.
Abstract: J-KAREN-P is a high-power laser facility aiming at the highest beam quality and irradiance for performing state-of-the art experiments at the frontier of modern science. Here we approached the physical limits of the beam quality: diffraction limit of the focal spot and bandwidth limit of the pulse shape, removing the chromatic aberration, angular chirp, wavefront and spectral phase distortions. We performed accurate measurements of the spot and peak fluence after an f/1.3 off-axis parabolic mirror under the full amplification at the power of 0.3 PW attenuated with ten high-quality wedges, resulting in the irradiance of ~1022 W/cm2 and the Strehl ratio of ~0.5.

80 citations


Journal ArticleDOI
TL;DR: In this paper, an all-dielectric meta-lens is proposed to collimate terahertz waves emitted from a tera-hertz antenna, which is not only thinner than a conventional bulk silicon lens, but also promises to eliminate the use of parabolic mirrors in a teraahertz time-domain spectroscopy system.
Abstract: We present an all-dielectric meta-lens designed to collimate terahertz waves emitted from a terahertz antenna. The meta-lens is not only thinner than a conventional bulk silicon lens, but also promises to eliminate the use of parabolic mirrors in a terahertz time-domain spectroscopy system. A systematic numerical study reveals that the meta-lens exhibits excellent performance in both the emitter and detector modules, converting between the spherical wave of the antennas and the collimated beam. The frequency and alignment dependences of the meta-lens are also investigated to comprehensively map its response characteristics. The all-dielectric meta-lens presented here may pave a way in developing high-performance integrated photoconductive terahertz antenna components.

25 citations


Journal ArticleDOI
TL;DR: In this article, the effect of gravity load on mirror shape and resulting slope and focus deviation values is characterized and quantified in finite element analyses referenced to specific lab tests, and the inner and outer ideally shaped parabolic mirror of RP3 geometry are evaluated for various discrete collector angles relevant for operation on different collector support structures.

24 citations


Journal ArticleDOI
TL;DR: In this article, a compound cylindrical solar concentrator (CCSC) was presented, which is comprised of cylinear Fresnel lenses, parabolic reflectors, and secondary reflectors.

22 citations


Journal ArticleDOI
TL;DR: In this article, the focusing properties of a single-point diamond turning parabolic mirror were evaluated with a single 174Yb + ion as a mobile point scatterer and the ion was trapped in a vacuum environment with a movable high optical access Paul trap.
Abstract: Focusing with a 4 π parabolic mirror allows for concentrating light from nearly the complete solid angle, whereas focusing with a single microscope objective limits the angle cone used for focusing to half solid angle at maximum. Increasing the solid angle by using deep parabolic mirrors comes at the cost of adding more complexity to the mirror’s fabrication process and might introduce errors that reduce the focusing quality. To determine these errors, we experimentally examine the focusing properties of a 4 π parabolic mirror that was produced by single-point diamond turning. The properties are characterized with a single 174Yb + ion as a mobile point scatterer. The ion is trapped in a vacuum environment with a movable high optical access Paul trap. We demonstrate an effective focal spot size of 209 nm in lateral and 551 nm in axial direction. Such tight focusing allows us to build an efficient light-matter interface. Our findings agree with numerical simulations incorporating a finite ion temperature and interferometrically measured wavefront aberrations induced by the parabolic mirror. We point at further technological improvements and discuss the general scope of applications of a 4 π parabolic mirror.

17 citations


Journal ArticleDOI
TL;DR: A novel multi-pass cavity design based on the use of a rotationally symmetric end mirror having a specifically designed spherical aberration so that its focal length varies inversely as the ray height from the optical axis is presented.
Abstract: We present a novel multi-pass cavity design based on the use of a rotationally symmetric end mirror having a specifically designed spherical aberration so that its focal length varies inversely as the ray height from the optical axis. We provide a detailed discussion of how ray tracing can be done for this system and show with numerical simulations that a very rich set of exotic spot patterns can be formed on the end mirrors. We further show a specific q-preserving configuration where the q-parameters of the input and output beams remain the same. Finally, we derive the polar form of the mirror surface profile that gives this offset-dependent focal length.

16 citations


Journal ArticleDOI
TL;DR: In this paper, the active surface adjustment in a deformed parabolic reflector antenna is analyzed and the results show that this method is more efficient in adjusting the surface and improving the working performance.
Abstract: The design of the Qitai 110 m Radio Telescope (QTT) with large aperture and very high working frequency (115 GHz) was investigated in Xinjiang, China. The results lead to a main reflector with high surface precision and high pointing precision. In this paper, the properties of active surface adjustment in a deformed parabolic reflector antenna are analyzed. To assure the performance of large reflector antennas such as gain and boresight, which can be obtained by utilizing an electromechanical coupling model, and satisfy them simultaneously, research on active surface adjustment applied to a new parabolic reflector as target surface has been done. Based on the initial position of actuators and the relationship between adjustment points and target points, a novel mathematical model and a program that directly calculates the movements of actuators have been developed for guiding the active surface adjustment of large reflector antennas. This adjustment method is applied to an 8 m reflector antenna, in which we only consider gravity deformation. The results show that this method is more efficient in adjusting the surface and improving the working performance.

16 citations


Journal ArticleDOI
TL;DR: In this article, the scattering of H- and E-polarized plane waves by a 2D parabolic reflector made of graphene and placed in the free space is studied numerically.
Abstract: The scattering of H- and E-polarized plane waves by a two-dimensional (2-D) parabolic reflector made of graphene and placed in the free space is studied numerically. To obtain accurate results we use the Method of Analytical Regularization. The total scattering cross-section and the absorption cross-section are computed, together with the field magnitude in the geometrical focus of reflector. The surface plasmon resonances are observed in the H-case. The focusing ability of the reflector is studied in dependence of graphene’s chemical potential, frequency, and reflector’s depth. It is found that there exists an optimal range of frequencies where the focusing ability reaches maximum values. The reason is the quick degradation of graphene’s surface conductivity with frequency.

15 citations


Journal ArticleDOI
TL;DR: An ion trap consisting of a reflective parabolic surface and a needle electrode and the micromotion of the ion is determined to be the limiting factor, and the result is consistent with theoretical calculation.
Abstract: Efficient fluorescence collection is the most challenging part in remote entangled ion qubit state generation. To address this issue, we developed an ion trap consisting of a reflective parabolic surface and a needle electrode. This parabolic trap design covers a solid angle of 2π steradians and allows precise ion placement at the focal point of the parabola. We measured (39 ± 3)% fluorescence collection from a single ion with this trap and analyzed the mirror optical performance. We observed single ion image spot size of 3.4 times diffraction limit, improved to 2.8 times diffraction limit with the help of an external deformable mirror. The micromotion of the ion is determined to be the limiting factor, and the result is consistent with theoretical calculation.

15 citations


Journal ArticleDOI
TL;DR: In this paper, a non-diffracting beam with a long depth of focus and a sub-half-wavelength spot size can be generated by tight focusing of a narrow annulus of azimuthally polarized beam with phase mask and a high-numerical-aperture parabolic mirror.
Abstract: We theoretically demonstrate a non-diffracting beam with a long depth of focus and a sub-half-wavelength spot size can be generated by tight focusing of a narrow annulus of azimuthally polarized beam with a phase mask and a high-numerical-aperture parabolic mirror. In this paper, numerical verifications are implemented in the calculation of the electromagnetic fields near the focus based on the vector diffraction theory. We present the expression of the approximate relationship between the angular thickness ∆θ and the depth of focus. We verify that the depth of focal line can be tunable by changing the value of ∆θ.

Journal ArticleDOI
TL;DR: In this paper, a new high-flux solar simulator was developed at the University of Colorado, which achieved a peak flux of 12.50 MW/m2 and a peak power of 9.190kW on a ∅10 cm target for a mean flux of 1.155mW.

Journal ArticleDOI
TL;DR: The ray tracing, optical simulation, and mockup experiment results exhibited that the illumination distribution met the regulation of ECE R112 class B, and the ideal efficiency could reach 96.8% in theory.
Abstract: A confocal reflector lamp with an asymmetric triangular prism was designed for a stacking illumination of a light emitting diode (LED) automobile headlamp fitting ECE R112 asymmetrical regulation. The optical system includes three 1st elliptic reflectors, three 2nd parabolic reflectors, and one asymmetric triangular prism. Three elliptic and parabolic reflectors were assembled with three confocal reflector modules; two modules projected the cut-off line of a 0° angle, and the other module projected the cut-off line of a 15° angle using of an asymmetric triangular prism. The ray tracing, optical simulation, and mockup experiment results exhibited that the illumination distribution met the regulation of ECE R112 class B, and the ideal efficiency could reach 96.8% in theory. The tolerance analysis showed the efficiency remained above 98% under the error values of ±0.2 mm of the position of the LED light source, and the y direction of the up-down movement was more sensitive than the x and z directions. The measurement results of the mockup sample safety factor were all larger than 1.15 and supported the regulation of the ECE R112 Class B.

Proceedings ArticleDOI
01 Sep 2017
TL;DR: In this article, the aperture power density function of a parabolic reflector fed by an ideal point is theoretically derived and accordingly a coaxial cavity horn feed is designed to make the power density functions constant on parabolic aperture surface and then on the QZ aperture, which realizes high QZ usage of the single parabolic CATR.
Abstract: Aperture usage is one of the most important problem in reflector-based compact antenna test range(CATR). Single reflector CATR provides very low aperture usage, normally 30%, because of the effects of edge diffraction. In order to solve this problem, serrated edges and rolled edges are generally chosen along the reflector's edge to reduce the edge diffraction field inside quiet zone(QZ) of the CATR. Even if edge diffraction has been handled by edge treatment, the QZ utilization rate of single reflector CATR (< 50%) is still low. Big reflector is therefore required to produce large QZ, which increases processing difficulty and construction cost. All of this means it is imperative to study reflector aperture distribution function and then design suitable feed's radiation field. In this paper, the aperture power density function of a parabolic reflector fed by an ideal point is theoretically derived and accordingly a coaxial cavity horn feed is designed to make the power density function constant on parabolic aperture surface and then on the QZ aperture, which realizes high QZ usage of the single parabolic CATR.

Journal ArticleDOI
TL;DR: In this article, an ion trap combining a reflective parabolic surface with trap electrodes was proposed to collect a single ion image spot size of about 3.4 times diffraction limit, improved to 2.8 times with the help of an external deformable mirror.
Abstract: Single trapped ion qubit is an excellent candidate for quantum computation and information, with additional ability to coherently couple to single photons. Efficient fluorescence collection is the most challenging part in remote entangled ion qubit state generation. To address this issue, we developed an ion trap combining a reflective parabolic surface with trap electrodes. This parabolic trap design covers a solid angle of 2pi steradians, and allows precise ion placement at the focal point of the parabola. We measured approximately 39% fluorescence collection from a single ion with this mirror, and analyzed the mirror optical performance. We observed single ion image spot size of about 3.4 times diffraction limit, improved to 2.8 times diffraction limit with the help of an external deformable mirror. The micromotion of ion is determined to be the limiting factor, and the result is consistent with theoretical calculation.

Proceedings ArticleDOI
19 Mar 2017
TL;DR: It is shown that a parabolic reflector “collar” that is placed around the antenna array can significantly reduce the shadowing in the far-field.
Abstract: In this paper, we propose a novel method to mitigate the strong shadowing effect a nearby finger has on the antenna of a handheld communications device operating at 60 GHz, by introducing reflectors on the device When the finger is located at the distance of 3 mm of the antenna, it causes strong shadowing and the far-field radiation attenuation behind the finger is 25–34 dB In this paper, we show that a parabolic reflector “collar” that is placed around the antenna array can significantly reduce the shadowing in the far-field With the collar, the far-field radiation behind the finger is improved by 19–25 dB, making the array usable even when covered by a finger The effect of reflector size and location is studied

Journal ArticleDOI
TL;DR: In this paper, a high-impedance surface (HIS)-based leaky-wave antenna excited by collimated surface wave (SW) is proposed, which consists of two identical SW launchers (SWLs) and an HIS structure.
Abstract: This letter presents a novel high-impedance surface (HIS)-based leaky-wave antenna excited by collimated surface wave (SW). The proposed antenna consists of two identical SW launchers (SWLs) and an HIS structure. Regarding the SWL, it is based on an offset-fed parabolic reflector. By using the substrate-integrated waveguide technique, the reflector system is integrated in the planar substrate. For the HIS, it is formed by a periodically arranged rectangular microstrip patch array. The proposed SWL can generate collimated SW with the $\rm {TM_0}$ propagation mode. With the perturbation of the HIS, the guided SW can be transformed to $m$ = $-$ 1 space-harmonic-mode leaky wave. In addition, in order to obtain efficient broadside radiation, an additional secondary slit is properly designed in each unit cell of the HIS to suppress the open-stopband effect. A prototype of the proposed antenna is demonstrated by both full-wave simulation and experimental verification. Continuous beam scan can be realized from $-36^\circ$ to $+35.5^\circ$ within the frequency range of 16–22 GHz.

Proceedings ArticleDOI
05 Sep 2017
TL;DR: In this paper, a magnetorheological finishing (MRF) was applied to the NEXCERA aspheric mirror from best fit sphere shape, which is regarded as the best suited process for a precise figure correction of the ultralightweight mirror with thin sheet due to its advantage of low normal force polishing.
Abstract: Ultra-low thermal expansion ceramics NEXCERATM is regarded as one of potential candidate materials crucial for ultralightweight and thermally-stable optical mirrors for space telescopes which are used in future optical missions satisfying extremely high observation specifications. To realize the high precision NEXCERA mirrors for space telescopes, it is important to develop a deterministic aspheric shape polishing and a precise figure correction polishing method for the NEXCERA. Magnetorheological finishing (MRF) was tested to the NEXCERA aspheric mirror from best fit sphere shape, because the MRF technology is regarded as the best suited process for a precise figure correction of the ultralightweight mirror with thin sheet due to its advantage of low normal force polishing. As using the best combination of material and MR fluid, the MRF was performed high precision figure correction and to induce a hyperbolic shape from a conventionally polished 100mm diameter sphere, and achieved the sufficient high figure accuracy and the high quality surface roughness. In order to apply the NEXCERA to a large scale space mirror, for the next step, a middle size solid mirror, 250 mm diameter concave parabola, was machined. It was roughly ground in the parabolic shape, and was lapped and polished by a computer-controlled polishing machine using sub-aperture polishing tools. It resulted in the smooth surface of 0.6 nm RMS and the figure accuracy of ~ λ/4, being enough as pre-MRF surface. A further study of the NEXCERA space mirrors should be proceeded as a figure correction using the MRF to lightweight mirror with thin mirror sheet.

Proceedings ArticleDOI
25 Jun 2017
TL;DR: Lightweight parabolic mirrors for solar concentrators have been fabricated using carbon fiber reinforced polymer (CFRP) and a nanometer scale optical surface smoothing technique as discussed by the authors, which improved the surface roughness of the CFRP surface from $\sim 3\mu\mathrm{m}$ root mean square (RMS) for as-cast to ~5 nm RMS after smoothing.
Abstract: Lightweight parabolic mirrors for solar concentrators have been fabricated using carbon fiber reinforced polymer (CFRP) and a nanometer scale optical surface smoothing technique. The smoothing technique improved the surface roughness of the CFRP surface from $\sim 3\mu\mathrm{m}$ root mean square (RMS) for as-cast to ~5 nm RMS after smoothing. The surfaces were then coated with metal, which retained the sub-wavelength surface roughness, to produce a high-quality specular reflector. The mirrors were tested in an 11x geometrical concentrator configuration and achieved an optical efficiency of 78% under an AM0 solar simulator. With further development, lightweight CFRP mirrors will enable dramatic improvements in the specific power, power per unit mass, achievable for concentrated photovoltaics in space.

Patent
08 Dec 2017
TL;DR: In this article, the authors proposed a space-borne microwave atmospheric sounding instrument, which comprises feed sources, calibration bodies, a motor, plane mirrors, parabolic reflectors, a scanning drive control module, multiplexers and receiver units.
Abstract: The invention relates to a space-borne microwave atmospheric sounding instrument, which comprises feed sources, calibration bodies, a motor, plane mirrors, parabolic reflectors, a scanning drive control module, multiplexers and receiver units. The motor is controlled by the scanning drive control module to drive the plane mirror to rotate. The plane mirrors reflect received electromagnetic wave signals to the parabolic reflectors in the form of plane waves by scanning the atmosphere and the calibration bodies. The parabolic reflectors realize secondary reflection to enable the plane waves to be reflected to the corresponding feed sources arranged opposite thereto. The multiplexers are used for separating the frequency of the electromagnetic wave signals received by the feed sources respectively. Each receiver unit comprises a plurality of receivers parallel with the output end of the corresponding multiplexer, and is used for receiving the electromagnetic wave signals matched with the frequency thereof. The space-borne microwave atmospheric sounding instrument has the advantages of being high in performance, high in integration, low in weight and low in power consumption.

Journal ArticleDOI
TL;DR: The tension truss antenna structure is an effective architecture for large and high-precision parabolic reflectors as discussed by the authors, where a parabolic surface is approximated by planar triangular facets formed using...
Abstract: The tension truss antenna structure is an effective architecture for large and high-precision parabolic reflectors. Here a parabolic surface is approximated by planar triangular facets formed using...

Proceedings ArticleDOI
06 Apr 2017
TL;DR: In this article, an action survey of the optical elements class named by generalized parabolic lens is cited, and the approximately analytical and numerical analysis of radiation transformation realized by the paraxial lens is described within the limits of different theories: geometrical-optics and wave.
Abstract: An action survey of the optical elements class named by generalized parabolic lens is cited in this paper. The approximately-analytical and numerical analysis of radiation transformation realized by the generalized parabolic lens is described within the limits of different theories: geometrical-optics and wave (paraxial and nonparaxial). The types of refracting aspherical surfaces described with power function are defined on base of the geometrical-optics analysis. The surfaces allow forming characteristic intensity distributions on an optical axis. A paraxial propagation of laser beam with an initial arbitrary power phase function is described with approximate analytical expressions which are agreed qualitatively with the geometrical-optics analysis. The obtained expressions are precise for exponents 1 and 4. A nonparaxial analysis is implemented on base of calculation of the Rayleigh-Sommerfeld integral with qualifying corrections. It is shown that essential growth of intensity in the focus happens at the exponent value from 1 to 2, and the maximal intensity is achieved in a middle of the range.

Patent
22 Sep 2017
TL;DR: In this article, a parabolic reflector antenna is mounted proximate the distal end of the coaxial waveguide structure and a sub-reflector is mounted in the same position as the central waveguide.
Abstract: Microwave antenna systems include a parabolic reflector antenna and a dual-band feed assembly. The dual-band feed assembly includes a coaxial waveguide structure and a sub-reflector. The coaxial waveguide structure includes a central waveguide and an outer waveguide that circumferentially surrounds the central waveguide. The sub-reflector is mounted proximate the distal end of the coaxial waveguide structure.

Proceedings ArticleDOI
01 Jul 2017
TL;DR: In this paper, a Cassegrain type reflectarray instead of a parabolic reflector was proposed to generate OAM mode using a single-antenna OAM antenna, which was fabricated and measured to generate the l = 1 OAM.
Abstract: In this paper, we propose how to generate OAM mode using a Cassegrain type reflectarray instead of parabolic reflector. The Cassegrain reflectarray antenna is fabricated and measured to generate the l = 1 OAM mode.

Journal ArticleDOI
TL;DR: This work proposes a practical solution to the problem of low signal level Raman scattering in bio-samples by enhancing the Raman signal using a parabolic reflector and finds that this microscope design is most suitable for turbid samples.
Abstract: Raman spectroscopy is well suited for readily revealing information about bio-samples. As such, this technique has been applied to a wide range of areas, particularly in bio-medical diagnostics. Raman scattering in bio-samples typically has a low signal level due to the nature of inelastic scattering of photons. To achieve a high signal level, usually a high numerical aperture objective is employed. One drawback with these objectives is that their working distance is very short. However, in many cases of clinical diagnostics, a long working distance is preferable. We propose a practical solution to this problem by enhancing the Raman signal using a parabolic reflector. The high signal level is achieved through the large light collection solid angle of the parabolic reflector while the long working distance is ensured by the novel design of our microscope. The enhancement capability of the microscope was demonstrated on four types of samples. Among these samples, we find that this microscope design is most suitable for turbid samples.

Proceedings ArticleDOI
09 Jul 2017
TL;DR: In this article, a planar reconfigurable metasurface is used as a parabolic reflector for antenna applications, which is composed of unit cells incorporating voltage-controlled varactor diodes.
Abstract: A planar reconfigurable metasurface is used as a parabolic reflector for antenna applications. The metasurface is composed of unit cells incorporating voltage-controlled varactor diodes, where the dispersion responses of the cells can be tailored. The phase characteristics of a parabolic reflector is engineered by judiciously controlling the bias voltage of the varactor diodes on the planar metasurface. The metasurface is illuminated by a microstrip patch antenna. Performed measurements show a directive radiated beam from the antenna system. Frequency agility and beam steering performances are also produced by reconfiguring the metasurface reflector.

Patent
22 Mar 2017
TL;DR: In this paper, an interferometer and a spectrograph are used for industrial field environments, which can be applied to industrial field environment environments and have the advantages of high environment adaptability, compact structure, small size, light weight, high stability, low cost and the like.
Abstract: The present invention provides an interferometer and a spectrograph. The interferometer includes a shell, a laser, a beam splitter, a plane mirror and a moving mirror scanning mechanism; the laser and the beam splitter are fixed on the shell; the plane mirror is used for reflecting a light beam; the moving mirror scanning mechanism includes a bracket, a swing arm, a pivot shaft, a first angle mirror, a second angle mirror and a driving device, wherein the bracket is fixed onto the shell, the swing arm is connected onto the bracket through the pivot shaft, the first angle mirror and the second angle mirror which are used for refracting the light beam reflected by the plane mirror are fixed on the swing arm and are symmetrically distributed at two sides of the beam splitter, and the driving device is connected with the swing arm. The spectrograph includes an interferometer, an infrared light source and a parabolic mirror. The interferometer and spectrograph of the invention have the advantages of high environment adaptability, compact structure, small size, light weight, high stability, low cost and the like, and can be applied to industrial field environments.

Patent
20 Oct 2017
TL;DR: In this paper, a quasi-Gaussian wave beam is transmitted through a corrugated waveguide and is radiated to a free space through a rotating parabolic reflector, where the phase distribution is adjusted and the phase difference of the wave beam cross section is eliminated.
Abstract: The invention discloses a system for realizing terahertz wave beam transmission and bunching. The system comprises a corrugated waveguide input/output window, a rotating parabolic reflector and a phase position correcting mirror. A quasi-Gaussian mode is transmitted through mode corrugated waveguide and is radiated to a free space through a corrugated waveguide input end. The rotating parabolic reflector receives the quasi-Gaussian wave beam. After focusing and reflection, the wave beam irradiates the phase position correcting mirror, phase distribution is adjusted and the phase difference of the wave beam cross section is eliminated so that the wave beam satisfies Gaussian distribution in the phase and field strength and can be well coupled to the corrugated waveguide corresponding to the output window.

Journal ArticleDOI
TL;DR: In this article, a complex source point can generate a beam field, which is employed to expand an arbitrary source via a complex extension of the surface equivalence principle, and then the complex source beam expansion method is applied to analyze the field of large reflector antennas via physical optics method.
Abstract: The physical optics method is a widely used radiation and scattering estimation for electrically large-scaled objects, and it is finally reduced to the calculation of highly oscillatory integrals. In this article, the physical optics integrals over the reflecting surface for an incident complex source point is evaluated here in closed form. A complex source point can generate a beam field, which is employed to expand an arbitrary source via a complex extension of the surface equivalence principle. Then the complex source beam expansion method is applied to analyze the field of large reflector antennas via physical optics method. Numerical examples are presented to illustrate the accuracy and efficiency of this complex source beam-physical optics hybrid method for analyzing general parabolic reflectors.

Journal ArticleDOI
TL;DR: In this article, a detection optics for the integration of Raman scattering and scanning probe microscopy at low temperature based on a parabolic mirror is presented, where half of the paraboloid mirror covers a solid angle of π corresponding to a numerical aperture.
Abstract: We report the development of a detection optics for the integration of Raman scattering and scanning probe microscopy at low temperature based on a parabolic mirror. In our set-up, half of the paraboloid mirror covers a solid angle of π corresponding to a numerical aperture of N.A. ≈ 0.85. The optical system can be used for far- and near-field spectroscopy. In the far field, the polarizations can be maintained to within 80%–90%. In combination with a scanning microscope (AFM/STM), tunneling or near-field experiments are possible with less than 10% loss of aperture. Our set-up provides ideal conditions for the future development of tip-enhanced Raman spectroscopy at low temperature.