Real-time imaging techniques involving light propagation are commonly applied in the fields of physics, chemistry, and biomedicine. However, conventional techniques provide only the intensity change associated with light propagation. Here, we propose an imaging technique to visualize the ultrafast behavior of the polarization state of a propagating light pulse with four different linear polarization components. This approach provides ultrahigh temporal resolution to observe the light in motion. We recorded a motion picture of a three-dimensional image of a light pulse propagating through a diffuser and a calcite crystal at 56.8 and 75.4 ps, respectively. This technique can contribute to revealing the polarization state of propagating light pulses in a medium and ultrafast phenomenon.
The reminiscence bump is the effect that people recall more personal events from their teenage period than from adjacent lifetime periods. The effect is generally found in studies that divide the results of participants, who were at least 40 years old, into age bins of 10 years. In this study, the temporal distribution of autobiographical memories of Japanese young and middle-aged adults was examined. Because the questionnaire was presented on the internet, many participants could take part (N = 252). By dividing the personal events into smaller age bins and applying a mathematical method that corrects for the increased recall of recent events, a reminiscence bump could be identified in the memories of young adults. The location of the reminiscence bump of young adults was similar to the location of the reminiscence bump of middle-aged adults.
Spatiotemporal information about light pulse propagation obtained with femtosecond temporal resolution plays an important role in understanding transient phenomena and light-matter interactions. Although ultrafast optical imaging techniques have been developed, it is still difficult to capture light pulse propagation spatiotemporally. Furthermore, imaging through a three-dimensional (3-D) scattering medium is a longstanding challenge due to the optical scattering caused by the interaction between light pulse and a 3-D scattering medium. Here, we propose a technique for ultrafast optical imaging of light pulses propagating inside a 3D scattering medium. We record an image of the light pulse propagation using the ultrashort light pulse even when the interaction between light pulse and a 3-D scattering medium causes the optical scattering. We demonstrated our proposed technique by recording converging, refracted, and diffracted propagating light for 59 ps with femtosecond temporal resolution.
Abstract Observing light propagation plays an important role in clarifying ultrafast phenomena occurring on femtosecond to picosecond time scales. In particular, observing the ultrafast behavior of polarized light is useful for various fields. We have developed a technique based on Polarization Light-in-Flight Holography, which can record light propagation as a motion picture that can provide information about the polarization direction. Here we demonstrate motion-picture recording of a phenomenon, which is characteristic of polarized light, by using the proposed technique. As a phenomenon, we adopted the behavior of a light pulse incident at Brewster’s angle. We succeeded in recording the light reflection of specific polarized light by the proposed optical setup. The method of recording the motion-picture, reconstruction procedure, and the quantitative evaluation of the results are demonstrated.
As a continuation of the previous research on lathes, we have studied the case similar to hat when the free end of the work was supported by a dead centre.
We proposed an optical method for imaging of a motion picture of sounds for selected frequency. We recorded three sounds of frequencies 39.5, 40.0, and 40.5 kHz with the frame rate of 100,000 fps by parallel phase-shifting digital holography and succeeded in imaging the sound for selected frequency.
We propose a simultaneous imaging technique of both sound propagations and spatial distribution of acoustic frequencies. We experimentally demonstrated the proposed technique for the acoustic waves of frequencies 39,500 and 40,500 Hz, which have close sound pressure. The sounds were recorded at the framerate of 100,000 fps by parallel phase-shifting digital holography. To obtain the distribution of the acoustic frequencies, the short-time Fourier transform analysis was applied. The simultaneous imaging was carried out by assigning the frequencies and the pixel values of the phase-difference images to the components of HSL color space. The images obtained by the proposed technique represent the frequencies with the hue in addition to the sound propagations with the luminance. We succeeded in imaging the spatiotemporal evolution of the spatial frequencies of the sounds.
We investigated reconstructed images of light-in-flight recording by holographic microscopy when recording conditions are changed. As the conditions, we focused on incident angle of the reference light pulse and that of the object light pulse.
The diffraction of a plane electromagnetic wave by an inclined parallel plate grating is treated by using the Weiner-Hopf technique. The problem is formulated in terms of the single Wiener-Hopf equation, which is then using a factorization and decomposition procedure. The solution is exact but formal in the sense that there is an infinite number of unknowns. Approximation procedures are presented and two forms of the approximate solution are derived. Based on the above analysis, numerical examples are given and the transmission characteristics of the grating are discussed.< >
