Dynamically Modulated GaN Whispering Gallery Lasing Mode for Strain Sensor

Abstract

The continuous development of strain sensors offers significant opportunities for improving human-machine interfaces and health monitoring. The dynamically modulated lasing mode is a novel approach to realize a flexible, noncontact, high color-resolvability, high-resolution, and ultrasensitive strain sensor. Here, a flexible strain sensor perceiving stress variations is reported via the dynamical regulation of a GaN whispering gallery lasing mode based on the piezoelectric effect. The refraction index of GaN shows a linear relationship with the applied external tensile strain, resulting in a redshift phenomenon of the lasing mode peak at room temperature due to the predominant function of the piezoelectric polarization in the GaN microwire. Compared with a strain sensor relying on the wavelength shift of a photoluminescence (PL) emission peak, the differences and advantages of a sensor based on the strain-induced lasing mode variation are also investigated and analyzed systematically. This strain sensor may serve as an essential step toward the color mapping of mechanical signals by optical methods, with potential applications in color-perceived touching sensing, noncontact stress measurement, laser modulation, and optical communication technologies.

InGaN/GaN multi-quantum well LED array for short-distance optical links

“…2g) exhibits diffraction peaks at around 34.7°and 34.9°, which are assigned to the (0002) crystal planes of GaN and AlN, respectively. 29,30 The Raman spectrum (Fig. 2h) further confirms the high crystalline quality of the GaN layer, with the appearance of the E 2 (high) phonon mode at 568.6 cm -1 and the A 1 (LO) phonon mode at 734.4 cm -1 .…”

InGaN/GaN multi-quantum well LED array for short-distance optical links

“…2g) exhibits diffraction peaks at around 34.7°and 34.9°, which are assigned to the (0002) crystal planes of GaN and AlN, respectively. 29,30 The Raman spectrum (Fig. 2h) further confirms the high crystalline quality of the GaN layer, with the appearance of the E 2 (high) phonon mode at 568.6 cm -1 and the A 1 (LO) phonon mode at 734.4 cm -1 .…”

Piezoelectric‐Effect Enhanced Perovskite Plasmonic Nanolasers

“…Nevertheless, the mechanisms leading to the movement of the plasmonic mode is attributed to altering of n eff (from ≈2.92 decreasing to ≈2.76), which is caused by the increased N e on the ScAu surface due to PPE of CPB (Figures S13 and S14, Note S3, Supporting Information). [26][27][28][29][30][31]44] This result pellucid explain the underlying mechanism of plasmonic spectral blueshift.…”

“…The compressive strain was applied on the ScAu/M/CPB device (CPBNB length ≈9 µm) by bending the flexible PEN substrate via 3D manual stages (Figure 3a inset, Method in Note S1, Supporting Information). [26][27][28][29][30][31] As P = 4.5 µJ cm −2 , ε = 0%, two distinct lasing modes emerged at the low-energy side of the SE peak (Figure 3a, Figure S10, Supporting Information). As applied ε increases from 0% to −1.02%, the lasing mode of the high-energy side occurred blueshift from 538 to 537.5 nm.…”

Impacts of the Lattice Strain on Light Emission in Layered Perovskite Thin flakes

“…This trend is in good agreement with the previously reported spectral behaviors of both 3D perovskite single crystals and 2D materials under uniaxial strains. [45][46][47][48][49][50][51] Notably, the PL peak of [C 6 H 5 (CH 2 ) 2 NH 3 ] 2 (CH 3 NH 3 ) 2 Pb 3 I 10 (n = 3) exhibited a significant redshift from 619.1 to 624.2 nm when applied strain varied from −0.97 to 0.97%, which was significantly larger than the redshift observed for n = 2 (573.7 to 575.7 nm) and n = 1 (523.9 to 524.6 nm) under similar conditions (Figure 2b; Figure S7a, Supporting Information). The corresponding optical bandgap (E g ) can be obtained from the PL peak position (𝜆) using the conversion formula: E g = hc/𝜆, where h is Planck's constant and c is the speed of light.…”

InGaN/GaN multi-quantum well LED array for short-distance optical links

“…2g) exhibits diffraction peaks at around 34.7°and 34.9°, which are assigned to the (0002) crystal planes of GaN and AlN, respectively. 29,30 The Raman spectrum (Fig. 2h) further confirms the high crystalline quality of the GaN layer, with the appearance of the E 2 (high) phonon mode at 568.6 cm -1 and the A 1 (LO) phonon mode at 734.4 cm -1 .…”

Piezoelectric‐Effect Enhanced Perovskite Plasmonic Nanolasers

“…Nevertheless, the mechanisms leading to the movement of the plasmonic mode is attributed to altering of n eff (from ≈2.92 decreasing to ≈2.76), which is caused by the increased N e on the ScAu surface due to PPE of CPB (Figures S13 and S14, Note S3, Supporting Information). [26][27][28][29][30][31]44] This result pellucid explain the underlying mechanism of plasmonic spectral blueshift.…”

“…The compressive strain was applied on the ScAu/M/CPB device (CPBNB length ≈9 µm) by bending the flexible PEN substrate via 3D manual stages (Figure 3a inset, Method in Note S1, Supporting Information). [26][27][28][29][30][31] As P = 4.5 µJ cm −2 , ε = 0%, two distinct lasing modes emerged at the low-energy side of the SE peak (Figure 3a, Figure S10, Supporting Information). As applied ε increases from 0% to −1.02%, the lasing mode of the high-energy side occurred blueshift from 538 to 537.5 nm.…”

Impacts of the Lattice Strain on Light Emission in Layered Perovskite Thin flakes

“…This trend is in good agreement with the previously reported spectral behaviors of both 3D perovskite single crystals and 2D materials under uniaxial strains. [45][46][47][48][49][50][51] Notably, the PL peak of [C 6 H 5 (CH 2 ) 2 NH 3 ] 2 (CH 3 NH 3 ) 2 Pb 3 I 10 (n = 3) exhibited a significant redshift from 619.1 to 624.2 nm when applied strain varied from −0.97 to 0.97%, which was significantly larger than the redshift observed for n = 2 (573.7 to 575.7 nm) and n = 1 (523.9 to 524.6 nm) under similar conditions (Figure 2b; Figure S7a, Supporting Information). The corresponding optical bandgap (E g ) can be obtained from the PL peak position (𝜆) using the conversion formula: E g = hc/𝜆, where h is Planck's constant and c is the speed of light.…”

InGaN/GaN multi-quantum well LED array for short-distance optical links

“…2g) exhibits diffraction peaks at around 34.7°and 34.9°, which are assigned to the (0002) crystal planes of GaN and AlN, respectively. 29,30 The Raman spectrum (Fig. 2h) further confirms the high crystalline quality of the GaN layer, with the appearance of the E 2 (high) phonon mode at 568.6 cm -1 and the A 1 (LO) phonon mode at 734.4 cm -1 .…”

Piezoelectric‐Effect Enhanced Perovskite Plasmonic Nanolasers

“…Nevertheless, the mechanisms leading to the movement of the plasmonic mode is attributed to altering of n eff (from ≈2.92 decreasing to ≈2.76), which is caused by the increased N e on the ScAu surface due to PPE of CPB (Figures S13 and S14, Note S3, Supporting Information). [26][27][28][29][30][31]44] This result pellucid explain the underlying mechanism of plasmonic spectral blueshift.…”

“…The compressive strain was applied on the ScAu/M/CPB device (CPBNB length ≈9 µm) by bending the flexible PEN substrate via 3D manual stages (Figure 3a inset, Method in Note S1, Supporting Information). [26][27][28][29][30][31] As P = 4.5 µJ cm −2 , ε = 0%, two distinct lasing modes emerged at the low-energy side of the SE peak (Figure 3a, Figure S10, Supporting Information). As applied ε increases from 0% to −1.02%, the lasing mode of the high-energy side occurred blueshift from 538 to 537.5 nm.…”

Impacts of the Lattice Strain on Light Emission in Layered Perovskite Thin flakes

“…This trend is in good agreement with the previously reported spectral behaviors of both 3D perovskite single crystals and 2D materials under uniaxial strains. [45][46][47][48][49][50][51] Notably, the PL peak of [C 6 H 5 (CH 2 ) 2 NH 3 ] 2 (CH 3 NH 3 ) 2 Pb 3 I 10 (n = 3) exhibited a significant redshift from 619.1 to 624.2 nm when applied strain varied from −0.97 to 0.97%, which was significantly larger than the redshift observed for n = 2 (573.7 to 575.7 nm) and n = 1 (523.9 to 524.6 nm) under similar conditions (Figure 2b; Figure S7a, Supporting Information). The corresponding optical bandgap (E g ) can be obtained from the PL peak position (𝜆) using the conversion formula: E g = hc/𝜆, where h is Planck's constant and c is the speed of light.…”