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1. Optothermal dynamics in whispering-gallery microresonators

   https://doi.org/10.1038/s41377-019-0239-6  

   Jiang, Xuefeng; Yang, Lan (December 2020, Light: Science & Applications)

   null (Ed.)

   Abstract Optical whispering-gallery-mode microresonators with ultrahigh quality factors and small mode volumes have played an important role in modern physics. They have been demonstrated as a diverse platform for a wide range of applications in photonics, such as nonlinear optics, optomechanics, quantum optics, and information processing. Thermal behaviors induced by power build-up in the resonators or environmental perturbations are ubiquitous in high-quality-factor whispering-gallery-mode resonators and have played an important role in their operation for various applications. In this review, we discuss the mechanisms of laser-field-induced thermal nonlinear effects, including thermal bistability and thermal oscillation. With the help of the thermal bistability effect, optothermal spectroscopy and optical nonreciprocity have been demonstrated. By tuning the temperature of the environment, the resonant mode frequency will shift, which can also be used for thermal sensing/tuning applications. The thermal locking technique and thermal imaging mechanisms are discussed briefly. Finally, we review some techniques employed to achieve thermal stability in a high-quality-factor resonator system. 

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2. Correlation of Atomic Force Microscopy Tapping Forces to Mechanical Properties of Lipid Membranes

   https://doi.org/10.1115/DETC2012-70233  

   Shamitko-Klingensmith, Nicole; Wambaugh, Kelley M.; Burke, Kathleen A.; Magnone, George J.; Legleiter, Justin (August 2012, ASME 2012 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference)

   There is considerable interest in measuring, with nanoscale spatial resolution, the physical properties of lipid membranes because of their role in the physiology of living systems. Due to its ability to nondestructively image surfaces in solution, tapping mode atomic force microscopy (TMAFM) has proven to be a useful technique for imaging lipid membranes. However, further information concerning the mechanical properties of surfaces is contained within the time-resolved tip/sample force interactions. The tapping forces can be recovered by taking the second derivative of the cantilever deflection signal and scaling by the effective mass of the cantilever; this technique is referred to as scanning probe acceleration microscopy. Herein, we describe how the maximum and minimum tapping forces change with surface mechanical properties. Furthermore, we demonstrate how these changes can be used to measure mechanical changes in lipid membranes containing cholesterol. 

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3. Magneto-optical tuning of ferromagnetic resonance in silicon-doped yttrium iron garnet

   https://doi.org/10.1063/5.0257906  

   Popov, Maksym A; Chumak, Hryhorii L; Klimov, Oleksandr; Shepelytskyi, Yurii; Rado, Janos; Reznik, Alla; Albert, Mitchell S; Page, Michael R; Srinivasan, Gopalan (April 2025, Journal of Applied Physics)

   This report is on experiments and theory on the process of optically stimulated electron population density redistribution in Si-substituted yttrium-iron garnet single crystals at 77 K. It was determined that a photo-induced uniaxial anisotropy field arose in the YIG:Si sample in response to illumination by quasi-linearly polarized laser (λ = 808 nm) leading to redistribution of Fe2+ ions among the nonequivalent octahedral sites. The photo-induced field was measured by variation of ferromagnetic resonance (FMR) frequencies in the X-band. The measured FMR frequency shift demonstrated a pronounced dependence on the polarization vector orientation with respect to crystallographic axes, in accordance with the theory discussed here. The frequency shift dependence on light intensity (for optimal polarization orientation) was found to be nearly linear, at least within the output intensity range of the optical source. The maximum frequency shift was −130 MHz for 75 mW applied optical power. A similar phenomenon was also observed at room temperature but was attributed to the sample heating by the incident light. The results presented here demonstrate the potential of the phenomenon for application in the development of ferrite signal processing devices with dual tuning by both magnetic field and optical irradiation. 

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4. Visible light photonic integrated Brillouin laser

   https://doi.org/10.1038/s41467-021-24926-8  

   Chauhan, Nitesh; Isichenko, Andrei; Liu, Kaikai; Wang, Jiawei; Zhao, Qiancheng; Behunin, Ryan O.; Rakich, Peter T.; Jayich, Andrew M.; Fertig, C.; Hoyt, C. W.; et al (December 2021, Nature Communications)

   Abstract Narrow linewidth visible light lasers are critical for atomic, molecular and optical (AMO) physics including atomic clocks, quantum computing, atomic and molecular spectroscopy, and sensing. Stimulated Brillouin scattering (SBS) is a promising approach to realize highly coherent on-chip visible light laser emission. Here we report demonstration of a visible light photonic integrated Brillouin laser, with emission at 674 nm, a 14.7 mW optical threshold, corresponding to a threshold density of 4.92 mW μm −2 , and a 269 Hz linewidth. Significant advances in visible light silicon nitride/silica all-waveguide resonators are achieved to overcome barriers to SBS in the visible, including 1 dB/meter waveguide losses, 55.4 million quality factor (Q), and measurement of the 25.110 GHz Stokes frequency shift and 290 MHz gain bandwidth. This advancement in integrated ultra-narrow linewidth visible wavelength SBS lasers opens the door to compact quantum and atomic systems and implementation of increasingly complex AMO based physics and experiments. 

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5. Electric Force Microscopy of Sample Having Appreciable Sample Impedance

   Dwyer, Ryan P.; Marohn, John A. (March 2019, NanoScientific)

   Kelvin probe force microscopy (KPFM) experiments are used to image capacitance and surface potential in a wide variety of samples. The widely used KPFM frequency-shift equation rests on assumptions that are questionable in samples having an appreciable impedance or whose properties evolve on a fast timescale. We present new equations describing the cantilever frequency and dissipation in a KPFM experiment carried out on a sample with an appreciable stationary or time-dependent impedance, such as a photovoltaic film, a battery material, or a mixed electronic-ionic conductors. 

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