Tariq Manzur

Bio: Tariq Manzur is an academic researcher from Naval Undersea Warfare Center. The author has contributed to research in topics: Laser & Free-space optical communication. The author has an hindex of 5, co-authored 47 publications receiving 227 citations.

Stand-off detection of solid targets with diffuse reflection spectroscopy using a high-power mid-infrared supercontinuum source

Abstract: We measure the diffuse reflection spectrum of solid samples such as explosives (TNT, RDX, PETN), fertilizers (ammonium nitrate, urea), and paints (automotive and military grade) at a stand-off distance of 5 m using a mid-infrared supercontinuum light source with 3.9 W average output power. The output spectrum extends from 750–4300 nm, and it is generated by nonlinear spectral broadening in a 9 m long fluoride fiber pumped by high peak power pulses from a dual-stage erbium-ytterbium fiber amplifier operating at 1543 nm. The samples are distinguished using unique spectral signatures that are attributed to the molecular vibrations of the constituents. Signal-to-noise ratio (SNR) calculations demonstrate the feasibility of increasing the stand-off distance from 5 to ∼150 m, with a corresponding drop in SNR from 28 to 10 dB.

Optical correlator based target detection, recognition, classification, and tracking.

Abstract: A dedicated automatic target recognition and tracking optical correlator (OC) system using advanced processing technology has been developed. Rapidly cycling data-cubes with size, shape, and orientation are employed with software algorithms to isolate correlation peaks and enable tracking of targets in maritime environments with future track prediction. The method has been found superior to employing maximum average correlation height filters for which the correlation peak intensity drops off in proportion to the number of training images. The physical dimensions of the OC system may be reduced to as small as 2 in.×2 in.×3 in. (51 mm×51 mm×76 mm) by modifying and minimizing the OC components.

Optical response of laser-doped silicon carbide for an uncooled midwave infrared detector

Abstract: Data reported in Table 1 of our earlier paper [Appl Opt 50, 2640 (2011)101364/AO50002640APOPAI1559-128X] are corrected

Room-Temperature Quantum Cascade Laser: ZnO/Zn 1− x Mg x O Versus GaN/Al x Ga 1− x N

Abstract: A ZnO/Zn1−xMgxO-based quantum cascade laser (QCL) is proposed as a candidate for generation of THz radiation at room temperature. The structural and material properties, field dependence of the THz lasing frequency, and generated power are reported for a resonant phonon ZnO/Zn0.95Mg0.05O QCL emitting at 5.27 THz. The theoretical results are compared with those from GaN/AlxGa1−xN QCLs of similar geometry. Higher calculated optical output powers [\( {P}_{\rm{ZnMgO}} \) = 2.89 mW (nonpolar) at 5.27 THz and 2.75 mW (polar) at 4.93 THz] are obtained with the ZnO/Zn0.95Mg0.05O structure as compared with GaN/Al0.05Ga0.95N QCLs [\( {P}_{\rm{AlGaN}} \) = 2.37 mW (nonpolar) at 4.67 THz and 2.29 mW (polar) at 4.52 THz]. Furthermore, a higher wall-plug efficiency (WPE) is obtained for ZnO/ZnMgO QCLs [24.61% (nonpolar) and 23.12% (polar)] when compared with GaN/AlGaN structures [14.11% (nonpolar) and 13.87% (polar)]. These results show that ZnO/ZnMgO material is optimally suited for THz QCLs.

Active layer design of THz GaN quantum cascade lasers

Abstract: The structural, material and field dependence of the THz lasing frequency is reported for a QCL based upon GaN/AlGaN heterostructures. The inter-subband transition initiated generation of THz followed by the LO-phonon assisted fast depopulation takes into account the appropriate energy band alignments. Valence and conduction band alignments incorporating spin-orbit and crystal field splitting as well as bi-axial strain are used to determine the conduction band offset as a function of Al-mole fraction. Determination of eigen states takes into account the spontaneous and piezoelectric polarization induced modification in the conduction band profile. A lower THz generation frequency is predicted for Ga-face GaN/AlGaN-based QCLs using the revised energy band alignments.

Inference in artificial intelligence with deep optics and photonics.

Abstract: Artificial intelligence tasks across numerous applications require accelerators for fast and low-power execution. Optical computing systems may be able to meet these domain-specific needs but, despite half a century of research, general-purpose optical computing systems have yet to mature into a practical technology. Artificial intelligence inference, however, especially for visual computing applications, may offer opportunities for inference based on optical and photonic systems. In this Perspective, we review recent work on optical computing for artificial intelligence applications and discuss its promise and challenges.

Hybrid optical-electronic convolutional neural networks with optimized diffractive optics for image classification.

Abstract: Convolutional neural networks (CNNs) excel in a wide variety of computer vision applications, but their high performance also comes at a high computational cost. Despite efforts to increase efficiency both algorithmically and with specialized hardware, it remains difficult to deploy CNNs in embedded systems due to tight power budgets. Here we explore a complementary strategy that incorporates a layer of optical computing prior to electronic computing, improving performance on image classification tasks while adding minimal electronic computational cost or processing time. We propose a design for an optical convolutional layer based on an optimized diffractive optical element and test our design in two simulations: a learned optical correlator and an optoelectronic two-layer CNN. We demonstrate in simulation and with an optical prototype that the classification accuracies of our optical systems rival those of the analogous electronic implementations, while providing substantial savings on computational cost.

ZnO as a Functional Material, a Review

Abstract: Zinc oxide (ZnO) is a fascinating wide band gap semiconductor material with many properties that make it widely studied in the material science, physics, chemistry, biochemistry, and solid-state electronics communities. Its transparency, possibility of bandgap engineering, the possibility to dope it into high electron concentrations, or with many transition or rare earth metals, as well as the many structures it can form, all explain the intensive interest and broad applications. This review aims to showcase ZnO as a very versatile material lending itself both to bottom-up and top-down fabrication, with a focus on the many devices it enables, based on epitaxial structures, thin films, thick films, and nanostructures, but also with a significant number of unresolved issues, such as the challenge of efficient p-type doping. The aim of this article is to provide a wide-ranging cross-section of the current state of ZnO structures and technologies, with the main development directions underlined, serving as an introduction, a reference, and an inspiration for future research.

Infrared and Raman spectroscopy techniques applied to identification of explosives

Abstract: This review summarizes the recent trends and developments of infrared and Raman spectroscopy applied to the identification of explosives that have been published over the past decade, focusing on the different fields where explosives were studied: homeland and international security, forensics, environmental, characterization of explosives, trace detection and fluorescence-free Raman analysis of explosives.