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Chin. Opt. Lett.
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550 MHz carbon nanotube mode-locked femtosecond Cr:YAG laser

We demonstrate a femtosecond Cr:YAG laser mode-locked by a carbon nanotube saturable absorber mirror (CNT-SAM) at a repetition rate of 550 MHz. By employing the CNT-SAM, which exhibits a modulation depth of 0.51% and a saturation fluence of 28 μJ/cm2 at 1.5 μm, we achieved a compact bulk Cr:YAG laser with self-starting mode-locked operation near 1.5 μm, delivering an average output power of up to ...
50 GHz optical true time delay beamforming in hybrid optical/mm-wave access networks with multi-core optical fiber distribution

We propose and experimentally validate an optical true time delay beamforming scheme with straightforwardintegration into hybrid optical/millimeter (mm)-wave access networks. In the proposed approach, the most complexfunctions, including the beamforming network, are implemented in a central office, reducing the complexityand cost of remote antenna units. Different cores in a multi-core fiber are u...
Photoacoustic characteristics of lipid-rich plaques under ultra-low temperature and formaldehyde treatment

Photoacoustic imaging (PAI) has been used to characterize the spatial and quantitative features of lipid-richatherosclerotic plaques with high sensitivity and specificity. In this Letter, we first validate that the ultra-lowtemperature and formaldehyde treatment have no effect on photoacoustic characteristics of the artery samples.Comparative experiments between the PAI and histological results de...
Robust fiber-based frequency synchronization system immune to strong temperature fluctuation

In order to make the fiber-based frequency synchronization system suitable for the use of large-scale scientific and engineering projects in which the ambient temperature of the fiber links change dramatically, we design a non-harmonic frequency dissemination system immune to strong temperature fluctuation. After the lab tests, in which the ambient temperature of the fiber fluctuates 40°C/day and ...
High power generation of adaptive laser beams in a Nd:YVO4 MOPA system

We report efficient power scaling of the laser output with an adaptive beam profile from an Nd:YAG dual-cavitymaster oscillator using a three-stage end-pumped Nd:YVO4 amplifier. We succeed in the fast switching of anexcited laser mode by modulating an acousto-optic modulator loss in a dual-cavity master oscillator, therebyachieving temporal modulation of the output beam profile. The outputs from t...
Metamaterials-based terahertz sensor for quick diagnosis of early lung cancer

We experimentally demonstrate a metamaterials (MMs)-based terahertz (THz) sensor to quickly distinguish the cancer tissues from normal tissues. The MMs-based THz sensor has two strong resonance absorption peaks at about 0.706 and 1.14 THz, respectively. When the sensor is covered with cancer tissues, the redshifts at about 0.706 and 1.14 THz are 31 and 19 GHz, respectively. However, if normal tiss...
Compressed sensing in synthetic aperture photoacoustic tomography based on a linear array ultrasound transducer

Photoacoustic tomography (PAT) has the unique capability of visualizing optical absorption inside several centimeters-deep biological tissue with a high spatial resolution. However, single linear-array transducer-based PAT suffers from the limited-view challenge, and thus the synthetic aperture configuration is designed that still requires multichannel data acquisition hardware. Herein, a feasible...
Influence of laser contrast on high-order harmonic generation from solid-density plasma surfaces

The influence of laser temporal contrast on high-order harmonic generation from intense laser interactions with solid-density plasma surfaces is experimentally studied. A switchable plasma mirror system is set up to improve the contrast by two orders of magnitude at 10 ps prior to the main peak. By using the plasma mirror and tuning the prepulse, the dependence of high-order harmonic generation on...
Intense keV IAP generation by orthogonally polarized multicycle midinfrared two-color laser fields

We theoretically investigate the attosecond pulse generation in an orthogonal multicycle midinfrared two-color laser field. It is demonstrated that multiple continuum-like humps, which consist of about twenty orders of harmonics and an intensity of about one order higher than the adjacent normal harmonics, are generated when longer wavelength driving fields are used. By filtering these humps, inte...
Gradation representation method using a binary-weighted computer-generated hologram based on pulse-width modulation

We propose a simple gradation representation method using a binary-weighted computer-generated hologram (CGH) to be displayed on a high-speed spatial light modulator that can be controlled by the pulse-width modulation technique. The proposed method uses multiple bit planes comprising binary-weighted CGHs with various pulse widths. The object points of a three-dimensional (3D) object are assigned ...
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