Electric field distribution of the optical fractal states in the transmission spectrum with different number of periods.

(a-d) The number of periods is N = 3, N = 4, N = 5, N = 6, respectively.</p

Number of channels with different thickness of dielectric slab <i>C</i>.

Number of channels with different thickness of dielectric slab C.</p

S1 Data -

We studied the optical fractal effect of the one-dimensional distributed feedback Bragg photonic crystals formed by semiconductor GaAs and dielectric TiO2. Light wave is transmitted in the intermediate dielectric slab and reflected back by the periodic photonic crystals at both ends, forming multiple fractal resonance output. The transmission channels expand exponentially by thickening the bulk in a cryogenic environment. The quality factor of each fractal resonant state improves with a greater periodic number of crystals. Furthermore, central wave of resonance has a blue-shift as the external pressure increases, while the influence of environment temperature on the fractal resonance could be ignored. It is hoped that our study can highlight the potential of these findings for designing multi-channel communication filters in cryogenic environments.</div

Transmittance spectra at different number of periods values.

(a-d) The number of periods is N = 3, N = 4, N = 5, N = 6, respectively.</p

Transmittance spectra with different initial thickness of dielectric slab <i>C</i>.

(a-d) The initial thickness is set to dco = 3dao, dco = 9dao, dco = 27dao, dco = 81dao, respectively.</p

Electric field distribution of the optical fractal states in the transmission spectrum with different initial thickness of dielectric slab <i>C</i>.

(a-d) The initial thickness is set to dco = 3dao, dco = 9dao, dco = 27dao, dco = 81dao, respectively.</p

Schematic diagram of the one-dimensional distributed feedback Bragg photonic crystal structure (<i>AB</i>)^<i>N</i><i>C</i>(<i>BA</i>)^<i>N</i>, with <i>N =</i> 3.

Schematic diagram of the one-dimensional distributed feedback Bragg photonic crystal structure (AB)NC(BA)N, with N = 3.</p

Fig 7 -

(a) The transmittance in the parameter space composed of temperature and normalized frequency. (b) The transmittance in the parameter space composed of pressure and normalized frequency. (c) The transmittance spectra corresponding to the external static pressures of P = 10 GPa, 11 GPa, and 12 GPa, respectively.</p

Fig 3 -

(a) The quality factor of the channel C1 varying with the number of periods. (b) The central wavelength of the channel C1 varying with the number of periods.</p

The ECG signal and processed ECG cycles of two samples.

<p>(a)–(b) sel39 m, and (c)–(d) sele0136 m. The ECG cycles in the first 10 seconds of the two signals were plotted, to make a clearer curve of the two signals. For (a) and (c), the horizontal axis is in seconds, and the vertical axis is in mV.</p