Pulsed Solid-State Lasers for a Novel Non-Contact Manipulation Method — "Optoacoustic Tweezers"

Professor Li Feng from Beijing Institute of Technology, Professor Li Zhiyuan from South China University of Technology, and Professor Guo Honglian from Minzu University of China, along with their teams, have utilized pulsed solid-state lasers combined with digital micromirror devices to generate programmable laser patterns. Through the photoacoustic effect, they achieved high-throughput manipulation of micrometer-scale particles. The related findings were published under the title “Programmable Photoacoustic Patterning of Microparticles in Air” in Nature Communications (2024) 15:3250.

Photoacoustic Effect in Thin Films Generates Lamb Waves — “Optoacoustic Tweezers”

Optical tweezers and acoustic tweezers enable non-contact manipulation of microscopic and mesoscopic objects, making them essential in fields such as cell biology, medicine, and nanotechnology. Each technology has its strengths: optical tweezers offer high precision and flexibility, while acoustic tweezers provide stronger manipulation forces. By combining the two, researchers have developed a novel approach — “optoacoustic tweezers.”

The team used the photoacoustic effect to generate localized Lamb wave fields that can map arbitrary laser pattern shapes. By using these localized Lamb waves to vibrate the surfaces of multilayer films, thousands of microscopic particles can be simultaneously arranged into desired patterns. Furthermore, by rapidly and continuously adjusting the laser shape, the particles dynamically flow along the corresponding elastic wave fields, forming frame-by-frame animations. This method integrates the programmable adaptability of optical tweezers with the powerful manipulation capability of acoustic waves, paving the way for wave-based manipulation technologies.

Pulsed Solid-State Laser — Nimma Series

The experimental setup uses Raycus Optoelectronics' Nd:YAG Q-switched laser (model Nimma-900, wavelength 532 nm, pulse width 6 ns, single-pulse energy 480 mJ, repetition rate 10 Hz). The laser beam is expanded and uniformly projected onto a digital micromirror device to form various patterns, which are then focused onto a stainless steel thin film, generating localized mechanical stress waves (Lamb waves). Microparticles on the film are arranged according to the vibration of these stress waves. Nanosecond lasers can output periodic pulse trains with high peak power (>MW/cm²), making them one of the ideal light sources for generating photoacoustic effects.

In addition, the derivative Nimma-L and Nimma-HG-Pro series have been fully upgraded for applications such as LiDAR and pulsed laser deposition. Interested parties are welcome to contact us for more information.

Product Features

• ·  Three-wavelength output: 1355 nm (266 nm), 1064 nm, and 532 nm

• ·  Single-lamp, dual-rod design with long xenon lamp lifetime and low maintenance cost

• ·  Equipped with an automatic phase-matching frequency-doubling module (NAPA), suitable for long-term reliable operation

Applications

• ·  Ozone LiDAR

• ·  Raman LiDAR

Product Features

1. Automatic phase-matching function with four-wavelength electric switching and coaxial output

2. Motorized attenuator with coaxial indicator beam

3. One-button operation — no need to open the cover for adjustments

Applications

• ·  Laser-Induced Fluorescence (LIF)

• ·  Pulsed Laser Deposition (PLD)

• ·  Pumping Dye Lasers