Tunable spectral shifts and spectral switches by controllable phase modulation

Abstract

In this work, we offer a novel and flexible approach of spectral switches which can be handled more simply by controlling the phase of the diffracted light field of a completely spatially coherent incident beam with spectral profile from a one-dimensional phase step. This scheme has the benefit of easy implementation by simply varying the height of a one-dimensional phase step which causes spectral switches to occur when the step height reaches certain critical values without modulating any properties of the light source. To illustrate this effect, an explicit and analytical expression at an observation point corresponding to the step edge is obtained and some numerical examples are given and examined experimentally. Finally, based on the obtained results, it is shown that this method with the capability of very short response time can be easily applied to information encoding and transmission.

Spectral switching-based fan-out architecture and information processing in free-space

“…The spectral line becomes redshifted on one side of these special distances, becomes blue-shifted on the other side, and breaks into two lines at the special distances [6,9]. This is the so-called phenomenon of spectral switching [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Recently, we carried out theoretical and experimental work to study the effect of polarization on interference-induced spectral shifts and spectral switching.…”

“…During the last few years, the study on this phenomenon and SSBIP has emerged as an area of great interest for the science and engineering researchers [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. The studies carried out so far show that if red-shift and blue-shift in spectral switching could be associated with information bits "1" and "0", the spectral flipping of diffracted light (near singular points) from lower frequency (red-shift) to higher frequency (blue-shift) or vice versa might be utilized for information encoding and information transmission in free-space [6].…”

“…The studies carried out so far show that if red-shift and blue-shift in spectral switching could be associated with information bits "1" and "0", the spectral flipping of diffracted light (near singular points) from lower frequency (red-shift) to higher frequency (blue-shift) or vice versa might be utilized for information encoding and information transmission in free-space [6]. Despite some experimental constraints, SSBIP has attracted considerable attention due to its unique features [1][2][3]. For example, spectral switching may be controlled through internal control mechanism as well as external control mechanism.…”

“…For example, spectral switching may be controlled through internal control mechanism as well as external control mechanism. In the former case, one may control spectral switching by changing the properties of light source namely coherence [6,9], polarization [4,10], phase [3], and intensity [1]. In the latter case, the user may control spectral switching by changing wedge of the aperture [11], slit separations [12], and diffraction angles [13].…”

“…Although spectral switching phenomenon and its applications have been studied by several research groups [1][2][3][4][5][6][7][8][9][10][11][12][13][14], most of the experimental work is carried out in CSIR-National Physical Laboratory, New Delhi, India [5,9,10,13,14]. Till date, this phenomenon has been studied with different optical setups.…”