2024

Optica Vol. 11, Issue 1, pp. 42-47 (2024)

Matan Iluz, Kobi Cohen, Jacob Kheireddine, Yoav Hazan, Amir Rosenthal, Shai Tsesses, and Guy Bartal

Abstract:

Silicon photonics leverages mature semiconductor technology to produce cost-effective and high-performance components for various applications in data centers, artificial intelligence, and quantum computing. While the geometry of photonic integrated circuits can be characterized by existing means, their optimal and accurate performance requires detailed characterization of the light propagating within them. Here we demonstrate the first, to our knowledge, direct visualization of the light as it travels inside photonic integrated circuits. We employ the natural nonlinear optical properties of silicon to directly map the electric field of the waves guided inside the integrated circuits, characterizing waveguides and multimode splitters while extracting various parameters of the device—all in real-time and in a noninvasive manner. Our approach for visualizing light inside photonic circuits is the only solution directly providing such information without any overhead or penalty, potentially making it a crucial component for the characterization of photonic circuitry, toward their improved design, fabrication, and optimization.

Imaging light within the MMI splitter. (a) Optical imaging of the MMI device. (b) Direct mapping of the light evolution inside an MMI device. The figure comprises exposures of seven different locations along the device, stitched together to track the evolution in the MMI. The rightmost exposure is at the single-waveguide input while the leftmost is of the two waveguides. (c) Zoom-in of (b). (d) Simulation results on a similar scale to (c). (b)–(d) show the intensity of the transverse electric field. Evidently, the experimental results are in excellent agreement with the simulation of light evolution in such a system.
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Optica Vol. 11, Issue 1, pp. 42-47 (2024)

Matan Iluz, Kobi Cohen, Jacob Kheireddine, Yoav Hazan, Amir Rosenthal, Shai Tsesses, and Guy Bartal

Journal of Biomedical Optics, Vol. 29, Issue S1

Tamar Harary, Michael Nagli, Nathan Suleymanov, Ilya Goykhman, Amir Rosenthal

Abstract:

Significance
Optical-resolution optoacoustic microscopy (OR-OAM) enables label-free imaging of the microvasculature by using optical pulse excitation and acoustic detection, commonly performed by a focused optical beam and an ultrasound transducer. One of the main challenges of OR-OAM is the need to combine the excitation and detection in a coaxial configuration, often leading to a bulky setup that requires physically scanning the ultrasound transducer to achieve a large field of view.

Aim
The aim of this work is to develop an OR-OAM configuration that does not require physically scanning the ultrasound transducer or the acoustic beam path.

Approach
Our OR-OAM system is based on a non-coaxial configuration in which the detection is performed by a silicon-photonics acoustic detector (SPADE) with a semi-isotropic sensitivity. The system is demonstrated in both epi- and trans-illumination configurations, where in both configurations SPADE remains stationary during the imaging procedure and only the optical excitation beam is scanned.

Results
The system is showcased for imaging resolution targets and for the in vivo visualization of the microvasculature in a mouse ear. Optoacoustic imaging with focal spots down to 1.3μm, lateral resolution of 4μm, and a field of view higher than 4 mm in both lateral dimensions were demonstrated.

Conclusions
We showcase a new OR-OAM design, compatible with epi-illumination configuration. This setup enables relatively large fields of view without scanning the acoustic detector or acoustic beam path. Furthermore, it offers the potential for high-speed imaging within compact, miniature probe and could potentially facilitate the clinical translation of OR-OAM technology.

In vivo MIP images of a portion of a mouse ear. (a) Region of interest of 4.2×3mm2 is highlighted in orange frame. (b) An MIP image corresponding to the FOV marked in orange obtained using trans-illumination configuration. (c) Region of interest of 2.5×5mm2 marked in green. (d) An MIP image corresponds to the FOV marked in green obtained using trans-illumination setup. A small part of the capillary network is enlarged on the right of the full image. (e) Magnified view of a 1D scan of two capillaries, indicated by a white dashed line is demonstrated to showcase the system resolution capabilities. (f) Region of interest of2×3mm2 marked in blue. (g) An MIP image corresponds to the FOV marked in blue obtained using epi-illumination setup.

Tamar Harary, Michael Nagli, Nathan Suleymanov, Ilya Goykhman, Amir Rosenthal

Tag: 2024

Unveiling the evolution of light within photonic integrated circuits.

Large-field-of-view optical-resolution optoacoustic microscopy using a stationary silicon-photonics acoustic detector.