Laser scanning microscope with electrical high-order modulation extraction module

Patent metadata

Field	Value
Publication number	US-12596243-B2
Application number	US-202418879168-A
Country	US
Kind code	B2
Filing date	Sep 4, 2024
Priority date	Sep 6, 2023
Publication date	Apr 7, 2026
Grant date	Apr 7, 2026

Abstract

A nonlinear laser scanning microscope with an electrical high-order modulation extraction module is provided to enhance image contrast/signal-to-noise ratio (SNR) based on first-order modulated nonlinear signals. Specifically, it uses a photodetector in the photon-to-electron conversion process. After the process, the frequency of the first-order modulation (1M) is extracted to obtain a better SNR, significantly improving the image contrast/SNR in laser scanning microscopy imaging. When the image contrast/SNR is improved to a certain extent, the image acquisition time can be shortened, and the imaging depth can be further extended, resulting in images obtained with first-order modulation (1M) having better quality than those obtained without signal modulation.

First claim

What is claimed is:

1 . An electrical high-order modulation extraction module, used to receive the RF sinusoidal signal output by a photodetector on a laser scanning microscope with a laser scanning frequency, characterized in that the electrical high-order modulation extraction module includes:
a DC blocking filter used to filter out the DC signal on the RF sinusoidal signal output by the photodetector; a function generator used to provide a local oscillation frequency, wherein the local oscillation frequency is an integer multiple of the laser scanning frequency; and a mixer having one end receives the RF sinusoidal signal output by the DC blocking filter and the other end receives the local oscillation frequency output by the function generator, and outputs an intermediate frequency signal, wherein the intermediate frequency signal is used to down-modulate the first-order or other high-order modulation (1M or HOMs) signals to the DC coordinate position, and transmit the intermediate frequency signal to a DAQ program for pixel reconstruction.

2 . The electrical high-order modulation extraction module according to claim 1 , characterized in that it further includes a phase shifter used to shift the relative angular difference between the LO signal and the RF signal by a set angular difference.

3 . The electrical high-order modulation extraction module according to claim 1 , characterized in that the intermediate frequency signal passes through a low-pass filter.

4 . The electrical high-order modulation extraction module according to claim 3 , characterized in that the intermediate frequency signal that has passed through the low-pass filter is first amplified by an amplifier and then filtered by the low-pass filter.

5 . The electrical high-order modulation extraction module according to claim 1 , characterized in that a down-modulation circuit is formed on a substrate, and the substrate is arranged in a geometric housing to form a portable functional module, with a first connection end and a second connection end formed at both ends of the functional module, wherein the first connection end is connected to a servo terminal, and the second connection end receives the RF sinusoidal signal output by the photodetector.

6 . An electrical high-order modulation extraction module, used to receive the RF sinusoidal signal output by a photodetector on a laser scanning microscope with a laser scanning frequency, characterized in that the electrical high-order modulation extraction module includes:
a DC blocking filter used to filter out the DC signal on the RF sinusoidal signal output by the photodetector; a first splitter used to split the RF sinusoidal signal that has passed through the DC blocking filter into a first optical path and a second optical path; a function generator used to provide a local oscillation frequency, wherein the local oscillation frequency is an integer multiple of the laser scanning frequency; a second splitter used to split the local oscillation frequency into a quadrature path and an in-phase path; a first mixer, one input end of the first mixer receives the sinusoidal signal of the first optical path, and the other input end receives the quadrature path, and outputs a first intermediate frequency signal, wherein the first intermediate frequency signal is used to down-modulate the first-order modulation (1M) signal to the DC coordinate position; and a second mixer, one input end of the second mixer receives the sinusoidal signal of the second optical path, and the other input end receives the in-phase path, and outputs a second intermediate frequency signal, wherein the second intermediate frequency signal is used to down-modulate the first-order modulation (1M) signal to the DC coordinate position; and wherein the first intermediate frequency signal and the second intermediate frequency signal are transmitted to an arithmetic unit for calculation, and then the calculated root mean square signal is transmitted to a DAQ program for pixel reconstruction.

7 . The electrical high-order modulation extraction module according to claim 6 , characterized in that the quadrature path is the local oscillation frequency passed through a 90-degree phase shifter.

8 . The electrical high-order modulation extraction module according to claim 6 , characterized in that the arithmetic unit is configured in a servo terminal.

9 . The electrical high-order modulation extraction module according to claim 6 , characterized in that the first intermediate frequency signal passes through a first low-pass filter, and the second intermediate frequency signal passes through a second low-pass filter.

10 . The electrical high-order modulation extraction module according to claim 9 , characterized in that the first intermediate frequency signal and the second intermediate frequency signal that have passed through the first low-pass filter and the second low-pass filter are first amplified by a first amplifier and a second amplifier, and then filtered by the first low-pass filter and the second low-pass filter.

11 . The electrical high-order modulation extraction module according to claim 6 , characterized in that a dual-phase demodulator circuit is formed on a substrate, and the substrate is arranged in a geometric housing to form a portable functional module, with a first connection end and a second connection end formed at both ends of the functional module, wherein the first connection end is connected to a servo terminal, and the second connection end receives the RF sinusoidal signal output by the photodetector.

12 . The electrical high-order modulation extraction module according to claim 1 or 6 , characterized in that the DC blocking filter is a band-pass filter (BPF).

13 . A method for adjusting the imaging quality of a laser scanning microscope using an electrical high-order modulation extraction module, characterized in that it includes the following steps:
providing a module manufactured by the electrical high-order modulation extraction module, and connecting the module with the laser scanning microscope and the servo terminal; obtaining and determining whether the laser repetition frequency and the LO signal frequency are the same, by obtaining the laser repetition frequency of the laser scanning microscope and the LO signal frequency generated by the function generator through the information displayed on the servo terminal, and determining whether the LO signal frequency is a multiple of the laser repetition frequency; correcting the LO signal frequency, by adjusting the LO signal frequency output by the function generator through the servo terminal when the LO signal frequency is not a multiple of the laser repetition frequency, so that the LO signal frequency is a multiple of the laser repetition frequency; providing a high-order modulation signal, by obtaining a down-modulated high-order modulation signal through the calculation of the module, and transmitting the down-modulated high-order modulation signal to the DAQ program configured in the servo terminal for pixel reconstruction; and adjusting the imaging quality, by the observer sequentially selecting a down-modulated signal (1M, 2M, 3M, . . . ), and transmitting the down-modulated signal to the DAQ, and the DAQ program sequentially performing pixel reconstruction.

Assignees

• National Yang Ming Chiao Tung Univ

Inventors

• Chan Ming-Che

Classifications

• G02B21/0076

  arrangements using fluorescence or luminescence · CPC title

• G02B21/00

  Microscopes · CPC title

• H03C99/00

  Subject matter not provided for in other groups of this subclass · CPC title

• G02B21/008 Primary

  Details of detection or image processing, including general computer control · CPC title