Adaptive dynamic range shift (ADRIFT) quantitative phase imaging

Abstract

Quantitative phase imaging (QPI) with its high-contrast images of optical phase delay (OPD) maps is often used for label-free single-cell analysis. Contrary to other imaging methods, sensitivity improvement has not been intensively explored because conventional QPI is sensitive enough to observe the surface roughness of a substrate that restricts the minimum measurable OPD. However, emerging QPI techniques that utilize, for example, differential image analysis of consecutive temporal frames, such as mid-infrared photothermal QPI, mitigate the minimum OPD limit by decoupling the static OPD contribution and allow measurement of much smaller OPDs. Here, we propose and demonstrate supersensitive QPI with an expanded dynamic range. It is enabled by adaptive dynamic range shift through a combination of wavefront shaping and dark-field QPI techniques. As a proof-of-concept demonstration, we show dynamic range expansion (sensitivity improvement) of QPI by a factor of 6.6 and its utility in improving the sensitivity of mid-infrared photothermal QPI. This technique can also be applied for wide-field scattering imaging of dynamically changing nanoscale objects inside and outside a biological cell without losing global cellular morphological image information.

High-Speed Imaging of Second-Harmonic Generation in MoS2 Bilayer under Femtosecond Laser Ablation

“…We could not observe extraordinary signals, for example, higher than four times that of the monolayer even when there was a strong coupling between the layers, as confirmed by the PL measurements. This is contrary to the behavior of the twisted bilayer graphene, which exhibits a large enhancement in the third-harmonic generation [ 37 ]. In addition, the peak angle ( φ s ) in the twisted region exhibits a value that follows the relation φ s = ( φ 1 – φ 2 )/2, as indicated by the dashed line in Figure 3 c. The relatively large deviation for θ twist > 40° is likely due to errors originating from weak signals, which originates from the destructive interference.…”

Ultrafast Fiber Lasers with Low-Dimensional Saturable Absorbers: Status and Prospects

“…After the discovery of graphene, it has been widely studied and investigated in various scientific research fields because of its distinctive nonlinear optical properties [ 31 , 54 , 136 ]. The features of broadband optical absorption, ultrafast carrier recovery, gapless band structure, and high damage threshold make graphene one of the leading SAs in the application of fiber laser lasers.…”

“…All of these LD-based tunable devices could also be investigated for various in-line all-fiber devices, such as ultrafast all-optical tunable switchers, optical limiters, all-optical modulators, polarizers etc., based on electrically/optically controlled nonlinear optical properties (i.e., higher-order susceptibility/nonlinearity, multiphoton absorption, etc.). The twist-angle in Bi-layer LD materials also can be engineered along with the externally (electrically and/or optically) controlled scheme to find the enhanced higher-order optical nonlinearity and SA properties for high performance, ultrafast and precisely controlled fiber lasers, and other nonlinear optical devices [ 54 ]. LD SA-based fs mode-locked ultrafast fiber lasers have grown emerging interest in space-borne applications, as they can sustain more than the life span of satellites [ 136 , 208 , 209 ].…”

“…2D materials have solid covalent bonding in a layer and weak interlayer van der Waals force. The electrons’ dynamic is limited in the 2D structure if there is no interference of interlayer interaction, which provides 2D materials with numerous novel optical and electrical characteristics [ 53 , 54 , 55 ]. Graphene is the earliest monoatomic 2D layer material revealed, with remarkable optical, electrical, mechanical, and thermal behaviors [ 40 , 41 , 42 , 43 , 44 , 45 ].…”

Bond-selective imaging by optically sensing the mid-infrared photothermal effect

“…Pleitez et al ( 32 ) demonstrated mid-IR photoacoustic microscopy with broad biomedical applications for monitoring carbohydrates, lipids, and proteins in cells and tissues. The Ideguchi group ( 62 ) recently reported the MIP quantitative phase imaging with depth-resolved capability and extended dynamic range ( 63 ).…”