We present results of what is to our knowledge the first experimental demonstration of simultaneous optical wavelength interchange by use of a two-dimensional second-order nonlinear photonic crystal. Fabrication and performance parameters of a 1535-1555-nm wavelength interchange nonlinear photonic crystal fabricated in lithium niobate are discussed.
An algorithm for generating optimal pseudorandom pulse position modulation (PRPPM) waveforms for ladar ranging is presented. Bistatic ladar systems using Geiger-mode avalanche photodiodes require detection of several pulses in order to generate sufficient target statistics to satisfy some detection decision rule. For targets with large initial range uncertainty, it becomes convenient to transmit a pulse train with large ambiguity range. One solution is to employ a PRPPM waveform. An optimal PRPPM waveform will have minimal sidelobes: equivalent to 1 or 0 counts after the pulse correlation filter (compression). This can be accomplished by generating PRPPM pulse trains with optimal or minimal sidelobe autocorrelation.
We demonstrate production of quantum correlated and entangled beams by second harmonic generation in a nonlinear resonator with two output ports. The output beams at λ = 428.5 nm exhibit 0.9 dB of nonclassical intensity correlations and 0.3 dB of entanglement.PACS numbers: 03.67. Mn,42.50.Dv,42.65.Ky Continuous light beams that exhibit nonclassical statistics are of interest as a tool for studying quantum fields [1] and for a number of applications that include precision measurements [2], writing subwavelength spatial structures [3], and as resources for quantum information and communication protocols [4]. The most successful and widely used approach to generating nonclassical light employs parametric down conversion in crystals with a quadratic nonlinearity. At the microscopic level non-classical correlations and entanglement arise due to the possibility of converting a single high frequency photon at 2ω into a pair of entangled lower frequency photons at ω.In order to experimentally generate nonclassical beams with carrier frequency ω one typically starts with a coherent source at ω which is frequency doubled to 2ω. The light at 2ω is then used to drive a downconversion process to generate nonclassical light at frequency ω. These multiple steps add to the complexity of the experimental arrangement and limit the possibility of generating nonclassical light at high frequencies. In this letter we demonstrate for the first time that nonclassical intensity correlations, as well as quadrature entangled beams, can be generated directly by frequency upconversion. In this way a coherent source at frequency ω produces quantum correlated beams at frequency 2ω.Consider the interaction geometry shown in Fig. 1 where a beam of frequency ω pumps a resonator that has two exit ports for the second harmonic beams at frequency 2ω. The cavity mirrors are assumed perfectly transmitting for the harmonic beams which are generated in a single pass of the intracavity pump field through the nonlinear crystal. It is well known that second harmonic generation (SHG) results in squeezing of the fundamental and harmonic beams [5]. The generation of multibeam correlations in second harmonic generation is less well studied than in the case of parametric down conversion. Calculations have demonstrated the existence of correlations between the fundamental and harmonic fields [6] including entanglement between the fundamental and harmonic fields [7] and entanglement in type II SHG in the fundamental fields alone [8]. The possibility of nonclassical spatial correlations in either the funda- mental or harmonic fields alone [9] and of entanglement in the fundamental field [10] has also been shown in models that include diffraction. Here we consider a situation where there are two harmonic output beams that share the same intracavity pump field. The common pump field couples the output beams, and our recent analysis of this interaction geometry [11] reveals that the two outputs exhibit nonclassical intensity correlations, as well as quadrature en...
Abstract. We demonstrate generation and frequency doubling of unit charge vortices in a linear astigmatic resonator. Topological instability of the double charge harmonic vortices leads to well separated vortex cores that are shown to rotate, and become anisotropic, as the resonator is tuned across resonance.
Large format arrays of coherent detectors enable several advanced EO sensing modes including aperture synthesis, turbulence compensation and velocity sensing. Coherent detector arrays that operate in a linear mode are desirable; however, they are often impractical because read-out'ss offering sufficient pixel density and A/D rates are not available. Photon-counting coherent detector arrays based on Geigermode Avalanche Photo-Diode (GmAPD) arrays are attractive because they offer large array format, and the output is digitized via the photon arrival times. Furthermore, asynchronous GmAPD arrays offer improved blocking efficiency which in turn improves the frequency fidelity. In fact, the response time of an asynchronous GmAPD macropixel exceeds the reset time of the individual detectors. In this paper we present the results of analysis, modeling and experiments that show the performance levels attainable with asynchronous GmAPD arrays.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.