Systems and Methods for Scaling Electromagnetic Apertures, Single Mode Lasers, and Open Wave Systems

Patent Status

Brief Description

The technology is based on photonic crystal apertures, nanostructured apertures that exhibit a quasi-linear dispersion at the center of the Brillouin zone together with a mode-dependent loss controlled by the cavity boundaries, modes, and crystal truncation. Open Dirac cavities protect the fundamental mode and couple higher order modes to lossy bands of the photonic structure. The technology was developed with an open-Dirac electromagnetic aperture, known as a Berkeley Surface Emitting Laser (BKSEL). 

The inventors demonstrate a subtle cavity-mode-dependent scaling of losses. For cavities with a quadratic dispersion, detuned from the Dirac singularity, the complex frequencies converge towards each other based on cavity size. While the convergence of the real parts of cavity modes towards each other is delayed, going quickly to zero, the normalized complex free-spectral range converge towards a constant solely governed by the loss rate of Bloch bands. The inventors show that this unique scaling of the complex frequency of cavity modes in open-Dirac electromagnetic apertures guarantees single-mode operation of large cavities.

The technology demonstrates scaled up single-mode lasing, and confirmed from far-field measurements. By eliminating limits on electromagnetic aperture size, the technology will enable groundbreaking applications for devices of all sizes, operating at any power level.

BACKGROUND

Single aperture cavities are bounded by higher order transverse modes, fundamentally limiting the power emitted by single-mode lasers, as well as the brightness of quantum light sources. Electromagnetic apertures support cavity modes that rapidly become arbitrarily close with the size of the aperture. The free-spectral range of existing electromagnetic apertures goes to zero when the size of the aperture increases. As a result, scale-invariant apertures or lasers has remained elusive until now. 

Surface-emitting lasers have advantages in scalability over commercially widespread vertical-cavity surface-emitting lasers (VCSELs). When a photonic crystal is truncated to a finite cavity, the continuous bands break up into discrete cavity modes. These higher order modes compete with the fundamental lasing mode and the device becomes more susceptible to multimode lasing response as the cavity size increases. 

Suggested uses

The invention can be: 

• integrated in silicon or other CMOS devices for light emission out of the chip
• used to manipulate cells and biological substances for trapping
• used in application for lidars especially where the efficiency and the weight are critical, such as in mobility applications or applications in laser surgery where the laser needs to be inserted in a small volume
• directly integrated with sensors for environmental monitoring as a single laser or as an array of lasers
• used to implement electronically controlled beam steering for lidars by placing an array of the proposed lasers in the focal plane of an imaging system
• inserted in a pn junction for making electrically pumped single mode lasers
• used with dye molecule for lasing using organic materials
• directly pumped optically as a diode.
• used to control electromagnetic emission from materials.
• used to scale up any open-system based on waves such as acoustic, quantum, or electronic systems

Advantages

• thin
• compact
• lightweight
• efficient, because power is emitted from all material in the aperture
• the fundamental mode depletes gain for other modes
• can be pumped both electrically and optically
• can be manufactured with conventional fabrication techniques such as CMOS nanofabrication; the technology contains structures on the order of the wavelength or smaller
• more scalable than any other single aperture lasers, offering a singular solution for small size, weight, and power (SWAP) devices
• can be implemented in any frequency, ranging from microwaves, terahertz, infrared, optics, and beyond

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