Experimental Controlled-NOT Logic Gate for Single Photons in the Coincidence Basis

We report a proof-of-principle demonstration of a probabilistic controlled-NOT gate for single photons. Single-photon control and target qubits were mixed with a single ancilla photon in a device constructed using only linear optical elements. The successful operation of the controlled-NOT gate relied on post-selected three-photon interference effects which required the detection of the photons in the output modes.Comment: 4 pages, 4 figures; minor change

Long Hole Film Cooling Dataset for CFD Development - Flow and Film Effectiveness

An experiment investigating flow and heat transfer of long (length to diameter ratio of 18) cylindrical film cooling holes has been completed. In this paper, the thermal field in the flow and on the surface of the film cooled flat plate is presented for nominal freestream turbulence intensities of 1.5 and 8 percent. The holes are inclined at 30 deg above the downstream direction, injecting chilled air of density ratio 1.0 onto the surface of a flat plate. The diameter of the hole is 0.75 in. (approx. 0.02 m) with center to center spacing (pitch) of 3 hole diameters. Coolant was injected into the mainstream flow at nominal blowing ratios of 0.5, 1.0, 1.5, and 2.0. The Reynolds number of the freestream was approximately 11,000 based on hole diameter. Thermocouple surveys were used to characterize the thermal field. Infrared thermography was used to determine the adiabatic film effectiveness on the plate. Hotwire anemometry was used to provide flowfield physics and turbulence measurements. The results are compared to existing data in the literature. The aim of this work is to produce a benchmark dataset for Computational Fluid Dynamics (CFD) development to eliminate the effects of hole length to diameter ratio and to improve resolution in the near-hole region. In this report, a Time Filtered Navier Stokes (TFNS), also known as Partially Resolved Navier Stokes (PRNS), method that was implemented in the Glenn-HT code is used to model coolant-mainstream interaction. This method is a high fidelity unsteady method that aims to represent large scale flow features and mixing more accurately

Optical head with two wavelengths in single path using holographic optical element

In this paper, we review a number of digital versatile disk (DVD) pickup designs and present a new structure with two wavelengths using a 780 nm integrated optical unit (IOU) and a 650 nm laser diode (LD) in a single optical path. The 780 nm IOU acts as a sensor for the 650nm system. Two returned beams of different wavelengths are diffracted by a holographic optical element (HOE) to the same detector. With this construction, the number of components is reduced and alignment is effectively simplified

Integrated optical unit design for the collinear holographic storage system

The optical configuration proposed by Optware Corporation has the features of recording the holographic versatile disk (HVD) and backwardly retrieving CD and DVD. This paper presents a novel design that applies the technology of integrated optical unit to the HVD system. This unit comprises a holographic optical element for splitting light and generating servo signal. A transmissive spatial light modulator (SLM) with central data part and outer-ring reference part is adopted for modulating the laser beams. A new outer-ring polarizer is accompanied with the SLM. Two lasers, one with 532 nm for the HVD and the other with 650 nm for the CD/DVD, are included in the unit. Analysis for the system was performed. Simulation results show the feasibility for implementing an integrated collinear holographic system with miniaturized size

Multiple-beam liquid crystal grating for the recordable optical pickup head

By combining the technology of a liquid crystal diffractive optical element with that of a multiple-beam grating, a novel multiple-beam liquid crystal grating is proposed for the application of recordable optical pickup heads. This grating has the function of generating seven diffracted beams with equal intensity in each order while applying a voltage to the device. It provides the switching ability between the single beam and multiple beams for writing data and reproducing data, respectively

Multimode grating using polymer-stabilized liquid crystals and novel electrodes

In this study we demonstrate a monolithic liquid crystal (LC) diffraction grating with multiple diffraction modes using the techniques of polymer stabilization and novel electrode design. It can be applied to a single-path rewritable optical pick-up (OPU) with multiple wavelengths for the tracking compatibility of CD, DVD, and blue-light storage systems. (c) 2007 Optical Society of America

Dynamic laser feedback noise measurement for the optical information storage system

The conventional measuring system of laser feedback noise for an optical pickup was specifically implemented only for laser diodes by using a static optical system. With no closed-loop servo control, it is impossible to measure the genuine laser noise distribution of a pickup while operating in an optical drive. By modifying the optical system of a commercial pickup, this study built up a system that was integrated with precision mechanical design, optical design, servo control design, and opto-electronic signal inspection for providing dynamic real-time laser feedback noise measurement. Using this system, some experimental results have been observed. The laser feedback noise is responsible to the focusing point within the linear range of an optical pickup head. It has the maximum value while the lens is on the best focus. The higher the environmental temperature, the noisier the laser output will be. Besides, the central frequency of noise is dependent on the disk rotation speed, and the noise level is reducible by increasing the disk rotation speed. (C) 2007 Society of Photo-Optical Instrumentation Engineers

Diffraction grating with dual modes for two-wavelength rewritable optical pickup heads

This paper discloses the configuration of a dual-mode three-beam grating which adopts the liquid-crystal (LC) modulator technologies and has the function of switching diffraction properties. With the specific design of the top, bottom, and complementary electrodes, the grating has the feature of being modulated by external electric field for generating two diffraction modes. Two modes corresponding to different diffraction directions and angles were verified by experiments. This device could be applied to the fabrication of a monolithic three-beam grating, which is necessary for the tracking detection of a rewritable two-wavelength optical head using a two-wavelength integrated laser diode (TWIN-LD)

Polarization-selective liquid-crystal device and its application to recordable integrated optical

A polarization-selective multiple-beam liquid crystal grating (MBLCG) was designed. It can be applied to an integrated optical unit (IOU) for a recordable optical pickup head in small form factor with the functions of recording data using a single beam and retrieving data using multiple beams, respectively. This device is constructed using the technologies of liquid crystal light modulator for switching diffraction effects of a single transmissive beam and multiple diffracted beams. The proposed IOU composes of a laser diode, a photodetector, a MBLCG and a holographic optical element (HOE). The optical axes of the MBLCG and HOE are mutually perpendicular so that the round-trip light efficiency of the IOU can be maximized. Experimental results show that the MBLCG is capable of generating seven diffracted beams with equal light intensities and polarization-selective corresponding to an incident beam of the ordinary or extraordinary state