Far-Field Diffraction Characteristics of a Time-Dependent Gaussian-Shaped Pulsed Beam from a Rectangular Aperture

Spectrum apodization of a time-dependent Gaussian pulse incident on the apodized circular aperture in far-field

“…It is also noted that Eq. (1) is usually used for a monochromatic incident field, u 0 ðp 0 ; tÞ ¼ U 0 ðp 0 ; oÞe Àjot , with a single frequency o and the constant complex amplitude U 0 ðp 0 ; oÞ, but it is also applicable for a broad-band incident pulse [1][2][3][4][5][6][7][8][9], which can be superposed by a monochromatic field via the Fourier integral, or for the incident pulse spectrum U 0 ðp 0 ; oÞ, which can be obtained by using the Fourier transform [13]. The circular apodized aperture is described by the following function:…”

“…Recently, there is increasing interests in ''aperture dispersion'', that is, the spectral changes of a short pulse resulting from the aperture diffraction [1][2][3][4][5][6][7][8][9]. It also includes the red or blue shift of the spectral intensity maximum or the distortion of the spectrum of the incident pulse.…”

Spectrum Compression of Gaussian Pulse from Central Obstructed Slit in the Far-Field*

“…It also includes the red or blue shift of the spectrum maximum or the distortion of the incident pulse spectrum. [1][2][3][4][5][6][7][8][9][10][11] It is well known that an aperture with a central obstruction can reduce the diffraction pattern width for a constant-intensity light wave; hence, it is used to enhance the resolving power of image-forming systems. 12,13) In this work, we study the spectral characteristics of a time-dependent Gaussian pulse when it is incident on a slit with a central obstruction, which has not been investigated previously.…”

Spectral shifts and spectral switches of a pulsed Gaussian beam from a rectangular aperture in the far field

“…So far, the anomalous spectral behaviour of spatially partially or fully coherent polychromatic light beams has been studied theoretically [5][6][7][8][9] and verified by experiments [10][11][12], which has extended the work in singular optics from monochromatic light to spatially partially or fully coherent polychromatic light. Recently, the studies on the anomalous spectral behaviour of ultrashort pulsed beams diffracted at limiting apertures have also been highlighted [13][14][15][16].…”

“…Though a rectangular aperture was used in [16], the incident pulses are assumed to be time-dependent Gaussian-shaped pulses with unit amplitude, and their results did not reveal clearly the effect of the aperture on the anomalous spectral behaviours of the diffracted ultrashort pulsed beam. The purpose of this paper is to study the far-field anomalous spectral behaviours of a space-time-dependent Gaussian pulsed beam passing through a rectangular aperture and to discuss the possibility of tunable spectral switching in the far field with the apertured pulsed beam just by varying the size of the rectangular aperture.…”