Femtosecond laser time shaping pulse active regulation and control method for realizing near field nanometer focusing

Abstract

The invention relates to a femtosecond laser time shaping pulse active regulation and control method for realizing near field nanometer focusing, and solves the problems that a laser confocal resolution is insufficient, STED (stimulated emission depletion) depends on fluorescent materials, the regulation and control flexibility of the nanometer focusing of a surface plasma is poor and the like. The method comprises the following steps that: firstly, processing to obtain a graphene modified composite nanosphere material; then, utilizing a femtosecond laser time shaping optical system to decompose a femtosecond laser monopulse into one series of femtosecond laser pulse trains which are mutually separated on a time domain; and finally, adopting the obtained femtosecond laser pulse trains to irradiate the graphene modified composite nanosphere material, and generating a localized near field enhancement effect in a contact surface area of the graphene modified composite nanosphere materialand a target material. The method does not need to consider the structure and the dimension parameter of the graphene modified composite nanosphere, and the active regulation and control of a near field nanometer focusing process can be realized only by regulating and controlling the time and polarization combination and the energy distribution of multiple pulses in the femtosecond laser time shaping pulse.

Description

technical field [0001] The invention belongs to the field of near-field optics, and in particular relates to an active control method for femtosecond laser time-shaping pulses for realizing near-field nano-focusing. Background technique [0002] Optical nanofocusing has many potential applications in the fields of physics, chemistry, and biomedicine, such as microscopy, detection, and nanomanufacturing, such as spatial high-resolution imaging, nanolithography, photothermal therapy, surface-enhanced Raman spectroscopy, and single-molecule detection. And so on, it has become a research hotspot in recent years. [0003] Existing optical nanofocusing techniques include laser confocal, stimulated emission depletion (STED) focusing and surface plasmon nanofocusing (SP) and so on. Although the prior art has made great progress in theory and engineering application, there are many defects more or less. [0004] Laser confocal is that the probe light emitted from a point light sour...

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Problems solved by technology

[0007] In order to solve the problems of insufficient confocal resolution of the above-mentioned lasers, dependence of STED on fluorescent materials, poor control flexibility of surface plasmon nano-focusing, and limited application range, the present invention proposes a femtosecond-based laser assisted by fluorescence-free materials. High-resolution nanofocusing method for active modulation of shaped pulses

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