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Optics has advanced through centuries of research into the fundamental properties of light and its interactions with matter. Within this rich history, one optical component stands out: the diffraction grating. Liquid crystals (LCs) have emerged as promising candidates in diffraction gratings. LCs are versatile and adaptable materials influenced by various external factors. Diffractive LC grating devices can be produced through methods such as photo alignment, using polymer walls, or employing patterned electrodes. However, photo alignment poses challenges in terms of manufacturing complexity, and using polymer walls is associated with some drawbacks, such as high driving voltage and slower response times, which must be considered in their application. Currently, research efforts are predominantly focused on manufacturing techniques involving patterned electrodes. In this review, we comprehensively explored the theoretical foundations underpinning diffraction gratings. Additionally, we summarized research on diffractive gratings based on LC using patterned electrodes and conducted a comparative analysis of the characteristics of each device. [ABSTRACT FROM AUTHOR]

Light‐induced manipulation techniques have been utilized to transport, trap, or levitate microscopic objects for a wide range of applications in biology, electronics, and photonics. Without making direct physical contact, they can provide simple yet powerful means for high‐precision assembly of microscale functional blocks and components within the integrated circuit platforms, thereby offering a viable alternative to the conventional heterogeneous integration techniques, such as wafer/die bonding and transfer printing. Using a microbubble‐based optofluidic pick‐and‐place assembly process, heterogeneous integration of compact III‐V semiconductor photodetectors on a silicon‐based photonic integrated circuit chip, enabling direct high‐speed vertical electrical contacts for significantly improved photogenerated carrier transit distance/time, is experimentally demonstrated. The microdisk‐shaped InGaAs p‐i‐n photodetector integrated on the silicon waveguide has a 3 dB bandwidth exceeding 50 GHz under the applied bias voltage of −1 V for near‐infrared wavelengths around 1.55 µm. The light‐induced optofluidic assembly will provide a promising route for seamless heterogeneous integration of various optoelectronic components with high‐speed and low‐noise electrical interconnection on the fully processed silicon photonic/electronic integrated circuit platforms. [ABSTRACT FROM AUTHOR]