“… 66 , 67 . The high temperatures generated enhance diffusion rates promoting impurity doping such as sulfur 68 – 70 and the reorganization of the crystal structure, resulting in a temperature-dependant change in the optical properties of 71 .We speculate that the effect of crystal structure reorganisation and mobility of sulfur in , results in stronger changes than what it can be induced by a change of the capping layer contribution. Figure 6 Resonant wavelength of the exposed RR against the injected optical power in the waveguide (−5.9–5.1 dBm) for a duration of 60 minutes, cladded with a crystalline 120 m long cell.…”
A new family of phase change material based on antimony has recently been explored for applications in near-IR tunable photonics due to its wide bandgap, manifested as broadband transparency from visible to NIR wavelengths. Here, we characterize $$\hbox {Sb}_{2} \hbox {S}_{3}$$
Sb
2
S
3
optically and demonstrate the integration of this phase change material in a silicon nitride platform using a microring resonator that can be thermally tuned using the amorphous and crystalline states of the phase change material, achieving extinction ratios of up to 18 dB in the C-band. We extract the thermo-optic coefficient of the amorphous and crystalline states of the $$\hbox {Sb}_{2}\hbox {S}_{3}$$
Sb
2
S
3
to be 3.4 x $$10^{-4}\hbox {K}^{-1}$$
10
-
4
K
-
1
and 0.1 x 10$$^{-4}\hbox {K}^{-1}$$
-
4
K
-
1
, respectively. Additionally, we detail the first observation of bi-directional shifting for permanent trimming of a non-volatile switch using continuous wave (CW) laser exposure ($$-5.9$$
-
5.9
to 5.1 dBm) with a modulation in effective refractive index ranging from +5.23 x $$10^{-5}$$
10
-
5
to $$-1.20$$
-
1.20
x 10$$^{-4}$$
-
4
. This work experimentally verifies optical phase modifications and permanent trimming of $$\hbox {Sb}_{2}\hbox {S}_{3}$$
Sb
2
S
3
, enabling potential applications such as optically controlled memories and weights for neuromorphic architecture and high density switch matrix using a multi-layer PECVD based photonic integrated circuit.
“… 66 , 67 . The high temperatures generated enhance diffusion rates promoting impurity doping such as sulfur 68 – 70 and the reorganization of the crystal structure, resulting in a temperature-dependant change in the optical properties of 71 .We speculate that the effect of crystal structure reorganisation and mobility of sulfur in , results in stronger changes than what it can be induced by a change of the capping layer contribution. Figure 6 Resonant wavelength of the exposed RR against the injected optical power in the waveguide (−5.9–5.1 dBm) for a duration of 60 minutes, cladded with a crystalline 120 m long cell.…”
A new family of phase change material based on antimony has recently been explored for applications in near-IR tunable photonics due to its wide bandgap, manifested as broadband transparency from visible to NIR wavelengths. Here, we characterize $$\hbox {Sb}_{2} \hbox {S}_{3}$$
Sb
2
S
3
optically and demonstrate the integration of this phase change material in a silicon nitride platform using a microring resonator that can be thermally tuned using the amorphous and crystalline states of the phase change material, achieving extinction ratios of up to 18 dB in the C-band. We extract the thermo-optic coefficient of the amorphous and crystalline states of the $$\hbox {Sb}_{2}\hbox {S}_{3}$$
Sb
2
S
3
to be 3.4 x $$10^{-4}\hbox {K}^{-1}$$
10
-
4
K
-
1
and 0.1 x 10$$^{-4}\hbox {K}^{-1}$$
-
4
K
-
1
, respectively. Additionally, we detail the first observation of bi-directional shifting for permanent trimming of a non-volatile switch using continuous wave (CW) laser exposure ($$-5.9$$
-
5.9
to 5.1 dBm) with a modulation in effective refractive index ranging from +5.23 x $$10^{-5}$$
10
-
5
to $$-1.20$$
-
1.20
x 10$$^{-4}$$
-
4
. This work experimentally verifies optical phase modifications and permanent trimming of $$\hbox {Sb}_{2}\hbox {S}_{3}$$
Sb
2
S
3
, enabling potential applications such as optically controlled memories and weights for neuromorphic architecture and high density switch matrix using a multi-layer PECVD based photonic integrated circuit.
“…As an example, Fig. 1c shows the dispersion in the values of refractive index of amorphous Sb 2 S 3 deposited by different techniques (RF sputtering [9,13], chemical bath deposition [14,15] and electrophoretic deposition [16]) and corresponding crystallized phases as found in literature. Additionally, several band gap values of the crystalline (from 1.27 to 1.71 eV) and absorption edge in the amorphous (from 2.05 to 2.20 eV) can be found in literature.…”
Section: Introductionmentioning
confidence: 93%
“…The bonding in this materials, known as metavalent bonding, lies between covalent and metallic, thus, valence electrons are neither fully localized, nor fully delocalized [23]. A strong electronic polarization due to electron delocalization in crystalline PCMs gives rise to a stark change in optical dielectric functions upon phase change, as largely demonstrated [9,13], chemical bath deposition [14,15] and electrophoretic deposition [16]) and corresponding crystallized phases.…”
Section: Phase Change Materialsmentioning
confidence: 99%
“…Although Ovshinsky mostly focused on the change in electrical resistance, a tremendous contrast between refractive index also occurs upon the amorphous-to-crystalline transition, e.g. in PCM GST a refractive index contrast of Δn ≈ 2.7 is reported, whereas for Sb 2 S 3 Δn ≈ 0.6 in the near-IR [14]. This behavior in PCMs has been attributed to a pronounced change in chemical bonding on the transition from amorphous to crystalline phase [22].…”
Section: Phase Change Materialsmentioning
confidence: 99%
“…The main benefit of ellipsometric measurements is the evaluation, for stratified bulk materials, of both the real and imaginary parts of the complex dielectric function ϵ = ϵ 1 + iϵ 2 (which relates to the refractive index, n, and extinction coefficient, k, ϵ = (n + ik) 2 ), through the ellipsometric angles Ψ and Δ, with no need for Kramers-Kronig transforms. Already many authors have relied on spectroscopic ellipsometry to establish the dielectric function of amorphous and crystalline phases of PCMs such as Ge 2 Sb 2 Te 5 [17][18][19], Sb 2 S 3 [9,13,14,20], Sb 2 Se 3 [13,20], among others. However, still challenges exist in establishing the dielectric function of these materials.…”
The demand for information processing at ultrahigh speed with large data transmission capacity is continuously rising. Necessary building blocks for on‐chip photonic integrated circuits (PICs) are reconfigurable integrated low‐loss high‐speed modulators and switches. Phase change materials (PCMs) provide unique opportunities for integration into PICs. Here, the investigation of layered gallium monosulfide (GaS) as a novel low‐loss PCM from infrared to optical frequencies is pioneered, with high index contrast (Δn ≈0.5) at the optical telecommunication band. The GaS bandgap switches from 1.5 ± 0.2 eV for the amorphous state to 2.1 ± 0.1 eV for the crystalline state. It is demonstrated that the reversible GaS amorphous‐to‐crystalline phase transition can be operated thermally and by picosecond green (532 nm) laser irradiation. The design of a reconfigurable integrated optical modulator on‐chip based on Mach‐Zehnder Interferometers (MZI) with the GaS PCM cell deposited on one of the arms for application is presented at the telecommunication wavelength of λ = 1310 nm, where the standard single mode optical fiber exhibits zero chromatic dispersion, and at λ = 1550 nm, where a minimum optical loss of 0.22 dB km−1 is obtained. This opens the route to applications such as reconfigurable modulators, beam steering using phase modulation, and photonic neural networks.
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