Integrated All-Optical Infrared Switchable Plasmonic Quantum Cascade Laser

Abstract

We report a type of infrared switchable plasmonic quantum cascade laser, in which far field light in the midwave infrared (MWIR, 6.1 μm) is modulated by a near field interaction of light in the telecommunications wavelength (1.55 μm). To achieve this all-optical switch, we used cross-polarized bowtie antennas and a centrally located germanium nanoslab. The bowtie antenna squeezes the short wavelength light into the gap region, where the germanium is placed. The perturbation of refractive index of the germanium due to the free carrier absorption produced by short wavelength light changes the optical response of the antenna and the entire laser intensity at 6.1 μm significantly. This device shows a viable method to modulate the far field of a laser through a near field interaction.

Mapping the electromagnetic field confinement in the gap of germanium nanoantennas with plasma wavelength of 4.5 micrometers

“…Group-IV semiconductors such as Si and Ge have the potential for direct integration in microelectronic platforms, 16,17 also allowing for fast optical switching. 18,19 In n-Ge, given a conductivity effective mass m* ¼ 0.12 m e and a screening constant e m;1 ¼ 16, k p ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi m à e 0 e m;1 =q e 2 n e p < 5 lm is expected if very high free electron concentrations n e in excess of 10 20 cm À3 are achieved (here m e and q e are the electron mass and charge, respectively). Nanoantennas have indeed been realized in the n-Ge material system epitaxially grown on the Si wafers; 20 however in that case, doping levels of about 0.2  10 20 cm À3 , obtained by co-deposition of the dopant P and Ge, have still limited the nanoantenna operation at k > 11 lm with k p ¼ 9.3 lm.…”

Tilted exposure microsphere nanolithography for high-throughput and mask-less fabrication of plasmonic molecules

“…Such a feature sizes are favorable to generating resonance response near infrared and visible regions of optical spectrums. Although, well-established techniques such as electron beam lithography [10] and focused ion beam lithography [11] can produce nanometer scale features with high accuracy and repeatability, they are not compatible with large area fabrication as well as they are costly, time consuming and suitable for single element fabrications [12][13][14][15][16]. Moreover, oil-immersed photolithography [17], interference photolithography [18], nano-imprint NV PS Micro Microspheres are deposited on the surface of a sample covered by photoresist.…”

Optomechanical beam steering by surface plasmon nanoantenna

“…SPs have recently been used applications for enhanced optical transmission [2,3] and biosensing [4][5][6]. Recently, SP based devices have been used for all-optical modulation [7][8][9][10][11]. More significantly, opto-mechanical coupling has been used for optical modulation and tuning [12][13][14], optical switching [11], photodetection [15,16], and optical gradient force sensing and manipulation [17][18][19].…”