Topic
Signal beam
About: Signal beam is a research topic. Over the lifetime, 1881 publications have been published within this topic receiving 20717 citations.
Papers published on a yearly basis
Papers
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TL;DR: In this paper, the two-photon sub-wavelength interference can exist in a general spontaneous parametric down-conversion (SPDC) for both type I and type II crystals.
Abstract: We theoretically discuss one-photon and two-photon double-slit interferences for spontaneous and stimulated parametric down-conversions. We show that the two-photon sub-wavelength interference can exist in a general spontaneous parametric down-conversion (SPDC) for both type I and type II crystals. We propose an alternative way to observe sub-wavelength interference by a joint-intensity measurement which occurs for only type I crystal in a higher gain of SPDC. When a signal beam injects into the crystal, it may create two interference patterns by two stimulated down-converted beams, showing no sub-wavelength interference effect.
8 citations
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18 Sep 2002TL;DR: In this paper, a direct optical modulation (DOM) type wavelength converter is provided, which does not require a continuous wave (CW) signal, or a semiconductor laser in itself, and reduces a coupling loss between the GC-SOA and an optical fiber while improving an emission threshold.
Abstract: A direct optical modulation (DOM) type wavelength converter is provided. The provided wavelength converter is a gain-clamped semiconductor optical amplifier (GC-SOA), which does not require a continuous wave (CW) signal, or a semiconductor laser in itself, and reduces a coupling loss between the GC-SOA or the semiconductor laser and an optical fiber while improving an emission threshold of a laser. Therefore, the provided wavelength converter converts a wavelength of an input signal beam having a low intensity by controlling the intensity of the input signal.
8 citations
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TL;DR: In this paper, positive optical gain around 5 cm−1 (∼21 dB/cm) has been observed in Er3+-doped Ba2NaNb5O15 single crystal using a pump and probe experimental setup.
Abstract: Positive optical gain around 5 cm−1 (∼21 dB/cm) has been observed in Er3+-doped Ba2NaNb5O15 single crystal using a pump and probe experimental setup. High power laser pulses at 532 nm have been used as the pump source in order to strongly populate the S43/2(H211/2) levels of the Er3+ ions due to ground state absorption. Low signal beam cw laser radiation at 850 nm has been used as the probe beam to stimulate the emission associated with the S43/2(H211/2)→I413/2 electronic transition of the Er3+ ions. The process has been modelized as a four level system, and its population has been analyzed and simulated in order to study the gain dynamics. Optical amplification of the probe signal has been observed during the first 60 μs, which represents a good agreement between the measured lifetime of the S43/2(H211/2) levels and the reported simulation.
8 citations
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07 Mar 2011
TL;DR: In this paper, an ultrasonic wave signal beam former and a beam forming method using the same are provided to reduce hardware complexity even though the hardware complexity increases if a sampling frequency is higher than an existing frequency.
Abstract: PURPOSE: An ultrasonic wave signal beam former and a beam forming method using the same are provided to reduce hardware complexity even though the hardware complexity increases if a sampling frequency is higher than an existing frequency. CONSTITUTION: An ultrasonic wave signal beam former comprises the following units. A sampling unit samples an ultrasonic wave signal by a sampling frequency which is N times higher than a central frequency that an array converter has. The array converter receives an ultrasonic wave signal reflected from a collection point. A memory unit stores the ultrasonic wave signal sampled in the sampling unit. A time delay calculating unit calculates a time delay value for selecting an ultrasonic wave signal to be interpolated among ultrasonic wave signals stored in the memory unit.
8 citations
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01 Jan 1995
TL;DR: In this paper, the efficiency of an optical quantum non-demolition (QND) measurement can be characterized using three criteria, which describe respectively the quality of the quantum measurement, the non-destruction of the signal, and the conditional variance of the output signal beam, given the output meter beam.
Abstract: The efficiency of an optical quantum non-demolition (QND) measurement can be characterized using three criteria, which describe respectively the quality of the quantum measurement, the non-destruction of the signal, and the conditional variance of the output signal beam, given the output meter beam (quantum-state-preparation criterion). Quantitative limits can be defined with respect to these criteria, delimiting “classical” and “quantum” domains of operation. We describe the implementation of two experiments which fulfill these criteria, using either three-level atoms inside a doubly-resonant optical cavity, or semiconductors light emitters and receivers.
8 citations