Acousto-optic imaging (AOI) is a non-invasive method that uses acoustic modulation to map the light fluence inside biological tissue. In many AOI implementations, ultrasound pulses are used in a time-gated measurement to perform depth-resolved imaging without the need for mechanical scanning. However, to achieve high axial resolution, it is required that ultrasound pulses with few cycles are used, limiting the modulation strength. In this Letter, we develop a new approach to pulse-based AOI in which coded ultrasound transmission is used. In coded-transmission AOI (CT-AOI), one may achieve an axial resolution that corresponds to a single cycle, but with a signal-to-noise ratio (SNR) that scales as the square root of the number of cycles. Using CT-AOI with 79 cycles, we experimentally demonstrate over four-fold increase in SNR in comparison to a single-cycle AOI scheme.
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http://dx.doi.org/10.1364/OL.392617 | DOI Listing |
We introduce and characterize a fast (50 kHz), long range (50 ps) and random-access optical delay line based on an acousto-optic deflector inserted in the Fourier plane of a zero-dispersion line. The advantages of this agile delay line are demonstrated in the context of impulsive stimulated Raman imaging in the low-frequency range (<200 cm). Besides fast imaging with a spectral resolution of 1.
View Article and Find Full Text PDFMaterials (Basel)
November 2024
School of Instrumentation and Opto-Electronic Engineering, Beihang University, Beijing 100191, China.
For the acousto-optic tunable filter (AOTF)-based spectral imaging systems, the diffraction efficiency of the AOTF is a primary factor affecting system throughput. Moreover, the distribution of the acoustic field within the AOTF fundamentally determines the device's diffraction efficiency. Thus, the design of an AOTF device including a transducer and absorber to achieve a uniform acoustic field distribution plays an important role in improving diffraction efficiency.
View Article and Find Full Text PDFMultifocal structured illumination microscopy (MSIM) is a popular super-resolution imaging technique known for its good probe compatibility, low laser power requirements, and improved imaging depth, making it widely applicable in biomedical research. However, the speed of MSIM imaging is typically constrained by the approaches employed to generate and scan the laser foci across the sample. In this study, we propose a flexible two-photon excitation MSIM method using a pair of acousto-optic deflectors.
View Article and Find Full Text PDFiScience
October 2024
Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany.
Recent advances in understanding how neuronal activity shapes developing brain circuits increasingly rely on G-dependent inhibitory chemogenetic tools (G-DREADDs). However, their mechanisms of action and efficacy in neurons with immature G signaling are elusive. Here, we express the G-DREADD hM4Di in glutamatergic telencephalic neurons and analyze its impact on CA1 pyramidal neurons in neonatal mice.
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