Abstract: The present disclosure belongs to the field of photoacoustic signal detection, and specifically relates to a quantum-enhanced all-optical photoacoustic signal detection device and method. The problem of low sensitivity of photoacoustic signals based on interference measurement is solved, and high-sensitivity detection of photoacoustic signals generated by living organisms including human bodies can be achieved. A degenerate optical parametric oscillator based on a first-type phase matching crystals is used for preparing a vacuum squeezed state light field, a coherent control technology is used for locking the squeezed angle to obtain the quadrature phase vacuum squeezed state, the prepared quadrature phase vacuum squeezed state light field is injected into the vacuum channel of a Michelson interferometer, and a balanced homodyne detection mode is used for achieving detection of the quantum-enhanced photoacoustic signals.

Abstract: An integral optical resonant cavity for frequency conversion is provided. The integral optical resonant cavity includes: a housing, a cavity-length adjustment device, a temperature control device and a nonlinear crystal provided in the temperature control device; a first plano-concave mirror and a second plano-concave mirror included in the cavity-length adjustment device and a nonlinear crystal form the optical resonant cavity; and light passes through the first plano-concave mirror, the nonlinear crystal and the second plano-concave mirror sequentially. The stability of the length of the optical resonant cavity is improved through an integral design thereof, and the stability of the temperature of the nonlinear crystal in the integral optical resonant cavity is improved through the temperature control device, thereby stably controlling relative phases between light fields for the frequency conversion in the resonant cavity.

Abstract: A method is disclosed for generating a sub-nanosecond pulse laser, using a voltage-increased type electro-optical Q-switched laser. The method includes: applying a square wave driving signal on a Pockels cell in an electro-optical Q-switched laser by using a Q-switch driver module, where the peak voltage of the square wave driving signal is higher than the quarter-wave voltage of the Pockels cell; and performing, by controlling the loss related to the electro-optical Q switch with a voltage of the driving signal increasing from 0 to the peak voltage, a change of the working state of the electro-optical Q switch from a switched-off state to a switched-on state, and then to a partially-switched-on state. The intracavity laser is exhausted within a quite short time, so that the pulse width of the laser is shortened, to implement sub-nanosecond operation of a pulse laser.