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The spectrum of a CW field whose phase experiences a periodic sawtooth modulation is analyzed. Two types of the sawtooth phase modulation are considered. One is created by combining many harmonics of the fundamental frequency. The second is…

Optics · Physics 2019-10-23 R. N. Shakhmuratov

Antenna arrays are widely used in wireless communication, radar systems, radio astronomy, and military defense to enhance signal strength, directivity, and interference suppression. We introduce a deep learning-based optimization approach…

Machine Learning · Computer Science 2025-04-25 David Lu , Lior Maman , Jackson Earls , Amir Boag , Pierre Baldi

We have developed terahertz frequency quantum cascade lasers that exploit a double-periodicity distributed feedback grating to control the emission frequency and the output beam direction independently. The spatial refractive index…

The generation of stable short optical pulses in mode-locked lasers is of tremendous importance for many applications. Mode-locking is a broad concept that encompasses different processes enabling short pulse formation. It typically…

This letter provides a simple but efficient technique, which allows each transmitter of an interference network, to exchange local channel state information with the other transmitters. One salient feature of the proposed technique is that…

Networking and Internet Architecture · Computer Science 2017-08-08 Chao Zhang , Samson Lasaulce , Vineeth S. Varma

Grating lobes arise from the periodic nature of element spacing in the optical phased array. Essentially, the phased array performs the Spatial Fourier Transform on light; the steering capability of the main lobe is governed by phase shift…

Applied Physics · Physics 2024-02-20 Bowen Yu , Dachuan Wu , Yasha Yi

Modulation of metasurfaces in time gives rise to several exotic space-time scattering phenomena by violating the reciprocity and generation of higher-order frequency harmonics. We introduce a new design paradigm for time-modulated…

Applied Physics · Physics 2018-12-31 Mohammad Mahdi Salary , Samad Jafar-Zanjani , Hossein Mosallaei

Known coherent metasurfaces control interference of waves of a given frequency with other coherent waves at the same frequency, either illuminating from a different direction or created as intermodulation products. In this paper, we…

Applied Physics · Physics 2023-03-22 M. H. Mostafa , A. Diaz-Rubio , M. S. Mirmoosa , S. A. Tretyakov

We investigate a theoretical model for a dynamic Moir\'e grating which is capable of producing slow and stopped light with improved performance when compared with a static Moir\'e grating. A Moir\'e grating superimposes two grating periods…

Optics · Physics 2021-07-14 Thomas E. Maybour , Devin H. Smith , Peter Horak

Low image contrast is a major limitation in transmission electron microscopy, since samples with low atomic number only weakly phase-modulate the illuminating electron beam, and beam-induced sample damage limits the usable electron dose.…

Instrumentation and Detectors · Physics 2024-03-19 Jeremy J. Axelrod

We design a resistive heater optimized for efficient and low-loss optical phase modulation in a silicon-on-insulator (SOI) waveguide and characterize the fabricated devices. Modulation is achieved by flowing current perpendicular to a new…

Space-time modulation adds another powerful degree of freedom to the manipulation of classical wave systems. It opens the door for complex control of wave behavior beyond the reach of stationary systems, such as nonreciprocal wave transport…

Classical Physics · Physics 2019-11-06 Junfei Li , Xiaohui Zhu , Chen Shen , Xiuyuan Peng , Steven A. Cummer

Frequency engineering of whispering-gallery resonances is essential in microcavity nonlinear optics. The key is to control the frequencies of the cavity modes involved in the underlying nonlinear optical process to satisfy its energy…

Coherent control of a system involves steering an interaction to a final coherent state by controlling the phase of an applied field. Plasmas support coherent wave structures that can be generated by intense laser fields. Here, we…

Plasma Physics · Physics 2015-06-02 Z. -H. He , B. Hou , V. Lebailly , J. A. Nees , K. Krushelnick , A. G. R. Thomas

Extending the cavity length of diode lasers with feedback from Bragg structures and ring resonators is highly effective for obtaining ultra-narrow laser linewidths. However, cavity length extension also decreases the free-spectral range of…

Reciprocal spin-orbit coupling (SOC) via geometric phase with flat optics provides a promising platform for shaping and controlling paraxial structured light. Current devices, from the pioneering q-plates to the recent J-plates, provide…

High-dimensional light field modulation demands precise control over multiple optical parameters, a capability critical for next-generation photonic systems. While liquid crystals offer inherent advantages in dynamic birefringence tuning,…

Optics · Physics 2025-04-22 Tian Xia , Quanzhou Long , Wanlong Zhang , Zhenwei Xie , Xiaocong Yuan

Theoretical studies of superradiant lasing on optical clock transitions predict a superb frequency accuracy and precision closely tied to the bare atomic linewidth. Such a superradiant laser is also robust against cavity fluctuations when…

Quantum Physics · Physics 2021-11-02 Anna Bychek , Christoph Hotter , David Plankensteiner , Helmut Ritsch

This study presents a shaped reset feedback control strategy to enhance the performance of precision motion systems. The approach utilizes a phase-lead compensator as a shaping filter to tune the phase of reset instants, thereby shaping the…

Systems and Control · Electrical Eng. & Systems 2025-03-20 Xinxin Zhang , S. Hassan HosseinNia

The methodology for a heterodyned laser-induced transient thermal grating technique for non-contact, non-destructive measurements of thermal transport in opaque material is presented. Phase-controlled heterodyne detection allows us to…