Optical phased array can be widely used in many fields benefiting from its superior performance. We designed and fabricated chirped grating antennas and uniform grating antennas for the optical phased array. The effective aperture of the chirped grating antennas is about twice that of the uniform grating antennas. The chirped grating optical phased array can receive the reflected signal of the object at a distance of 100 m, while the uniform grating optical phased array can only receive 50 m under the same conditions. Additionally, a ranging distance of 25 m is achieved when two chirped grating optical phased arrays are set as the transmitter and receiver.
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http://dx.doi.org/10.1364/OE.464358 | DOI Listing |
Sensors (Basel)
December 2024
Department of Mechanical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.
Adhesive joining has the severe limitation that damages/defects developed in the bondline are difficult to assess. Conventional non-destructive examination (NDE) techniques are adequate to reveal disbonding defects in fabrication and delamination near the end of service life but are not helpful in detecting and monitoring in-service degradation of the joint. Several techniques suitable for long-term joint integrity monitoring are proposed.
View Article and Find Full Text PDFSensors (Basel)
November 2024
School of Information Engineering, Huzhou University, Huzhou 313000, China.
We report the development of a robust Yb-doped fiber laser system based on chirped-pulse amplification (CPA), generating 44-fs laser pulses with up to 70-µJ pulse energy at a 1-MHz repetition rate. It consists of a Yb-doped nonlinear polarization evolution (NPE) mode-locked fiber oscillator, a chirped fiber Bragg grating (CFBG) stretcher, a wave-shaper for manipulating the spectrum of the signal, cascaded fiber amplifiers, and two compression units. The output pulse duration of 44 fs for efficient high harmonic generation (HHG) was achieved by a multi-pass multi-plate Herriott-type non-linear compression unit.
View Article and Find Full Text PDFIn this study, we demonstrated a few-cycle pulse generation system delivering an 8-fs and 13-nJ pulse. The oscillator of this system is a mode-locked fiber laser based on a nonlinear amplifying loop mirror (NALM), which is injected into the gain management nonlinear (GMN) amplifier after pre-chirp management by a chirped fiber Bragg grating (CFBG) and a passive fiber. Subsequently, a hollow-core photonic bandgap (HC-PBG) fiber is employed to compensate for the dispersion, achieving a pulse duration of 49.
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