Photonic crystal nanocavities fabricated from chalcogenide glass fully embedded in an index-matched cladding with a high Q-factor (>750,000)

Abstract

We have designed and fabricated a 2-D photonic crystal heterostructure cavity in the chalcogenide glass Ge 11.5 As 24 Se 64.5 that is fully embedded in a cladding with refractive index of 1.44. The low index contrast of this structure (≈1.21) means that high-Q resonances cannot be obtained using standard hetero-structure cavity designs based on W1 waveguides. We show that reducing the waveguide width can substantially improve light confinement, leading to high-Q resonances in a heterostructure cavity. Numerical simulations indicate intrinsic Q v > 10 7 are possible with this approach. Experimentally, an optical cavity with a high intrinsic Q v >7.6 x 10 5 was achieved in a structure with a theoretical Q v = 1.7 x 10 6 .

Optical properties of point-defect nanocavity implemented in planar photonic crystal with various low refractive index cladding materials

“…These structures are analyzed and compared in the next section. Moreover, from the viewpoint of fabrication, these designs can be easily fabricated [14,16,18,20,21]. An asymmetric PhC structure with L3 point-defect cavities was fabricated using SOI substrates [14].…”

“…Furthermore, when 2D PhCs are fully cladded by air, continuous oxidation and unavoidable contamination can affect the structural characteristics of the photonic device [13]. To address these problems, various investigations have focused on planar PhC nanocavities partially or fully clad by low-RI materials [14][15][16][17][18][19][20][21][22][23].In particular, cavities made of planar PhCs with three missing holes linearly arranged (L3) are attracting considerable interest for applications involving high-qualityfactor (high-Q) nanocavities because these structures can selectively confine light of various wavelengths. PhC L3 nanocavities with high-Q factors and a small cubic-wavelength volume are used for all-optical switching [8], lowthreshold lasing [4-6], cavity quantum electrodynamics [7,10], and to control ultrafast laser pulses [24].…”

“…Furthermore, when 2D PhCs are fully cladded by air, continuous oxidation and unavoidable contamination can affect the structural characteristics of the photonic device [13]. To address these problems, various investigations have focused on planar PhC nanocavities partially or fully clad by low-RI materials [14][15][16][17][18][19][20][21][22][23].…”

Enhanced complete photonic bandgap in a moderate refractive index contrast chalcogenide-air system with connected-annular-rods photonic crystals

“…Making use of the photonic band gap (PBG) property of chalcogenide photonic crystals (PCs), various powerful functional optical devices have been designed or fabricated [2,3,[6][7][8][9][10][11][12][13][14]. If the PBG is increased, the performance of these PC devices would be further improved.…”

“…However, currently both the theoretical design and fabrication of three-dimensional (3D) PCs are challenging. Therefore, much attention has been put into the twodimensional (2D) chalcogenide PC [2,3,[6][7][8][9][10][11][12][13][14]. In the 2D PC, the modes of light waves could be decomposed into transverseelectric (TE) and transverse-magnetic (TM) polarizations.…”