Improved performance of polarization-stable VCSELs by monolithic sub-wavelength gratings produced by soft nano-imprint lithography

Abstract

We present a novel method for fabricating polarization-stable oxide-confined single-mode GaAs based vertical cavity surface emitting lasers (VCSELs) emitting at 850 nm using a new soft-lithography nano-imprint technique. A monolithic surface grating is etched in the output mirror of the laser cavity using a directly imprinted silica-based sol-gel imprint resist as an etch mask. The opto-electronic performance of these devices is compared to VCSELs fabricated by state-of-the-art electron-beam lithography. The lasers made using the soft nano-imprint technique show single-mode TM lasing at a threshold and laser slope similar to that of devices made by e-beam lithography. The soft nano-imprint technique also enables the fabrication of gratings with sub-wavelength pitch, which avoids diffraction losses in the laser cavity. The resulting single-mode VCSEL devices exhibit 29% enhanced efficiency compared to devices equipped with diffractive gratings.

Optoelectronic Enhancement of Ultrathin CuIn1–xGaxSe2 Solar Cells by Nanophotonic Contacts

“…The SCIL approach combines rapid and high fidelity waferscale replication of nanoparticle arrays, tolerance of substrate defects, and room temperature atmospheric processing. [29] A detailed description of the nanophotonic contact preparation is available in Experimental Section: Fabrication of SiOx nanoparticles on ITO substrates. The conformal coating of the nanopatterned electrode satisfies the geometrical requirement for a good electrical contact.…”

Nanoscale spatial limitations of large-area substrate conformal imprint lithography

“…The demonstrated average pitch variation of less than 0.1 nm over a 25×25 mm 2 area represents a very high replication fidelity [45,46], which is fully attributed to the in-plane stiffness of the glass support of the PDMS layers. Printing these high-fidelity nanopatterns on active semiconductor materials enables the realization of polarizationcontrolled LEDs or lasers [47] as well as photonic crystals [48].…”

Nanocontact printing stamp material via bi-functionalization of polyhedral oligomeric silsesquioxanes

“…Due to the fast parallel patterning method with high throughput and high resolution [16], production methods using UV-NIL are important in optics and photonics [17]. Fields of application can be found in wafer level cameras [18], lasers [19,20], solid state lighting (LEDs) [21], highdensity data storage [22,23] and biotechnology [24].…”