Nanophotonics – Page 2

Quantum plasmonics

A typescript of the same title appeared last week on the arXiv. The authors briefly review the field, quantum plasmonics, which combines the topics of quantum optics and plasmonics. The roots of plasmonics are found in the 1950’s work of Pines and Hopfield. However, it was not until the 2000’s that investigations began in earnest of effects like quantum entanglement, quantum size effects, and quantum tunneling, all mediated by plasmons (and/or polaritons).

Although the body of this review is brief, the authors do cite 153 references, giving one a thorough introduction to the relevant literature.

Reference: MS Tame et al., “Quantum Plasmonics”, arXiv:1312.6806
[Published about a year ago in Nature Physics, DOI:10.1038/nphys2615]

Photo-generated THz antennas

We have seen many publications on the topic of surface plasmon polaritons (SPP) in semiconductors. The patterns taken by the SPPs have invariably been static either in space, in time or in both. Experimentalists in The Netherlands recently used optical pumping to generate localized SPPs dynamically. This was achieved by inserting spatial light modulation (SLM) in the optical pump path. For the sake of clean, definitive experiments, the authors reported [arXiv:1309.7190] THz wave extinction by pseudo-randomly spaced dipoles of fixed lengths. In their conclusions, they point to exciting possible extensions (e.g., spatial and temporal control of resonant frequencies and local field enhancements).

Cathodoluminescence lithography

In a brief paper in Applied Physics Letters, a group from the Solid State Physics department at TU Berlin report an interesting process to build isolating mesas to support single quantum dots. Given a random distribution of quantum dots on a surface, one can select specifically those which suit one’s purposes as follows. Coat the sample with PMMA, scan with an electron beam thereby exciting cathodoluminescence from the quantum dots. Return the beam to the selected locations and invert the resist tone. Develop, etch, ash, etc. This leaves the selected quantum dots isolated from one another, each on its own small mesa. Apparently, the dose required to acquire sufficient luminescence signal is enough to fully expose the PMMA (in the positive sense). This is why the polymerization (tone reversal) step is needed.

The paper can also be found on the arXiv.

Nanoscribe GmbH

Nanoscribe GmbH has an impressive technology for 3D patterning. Based on non-linear two-photon lithography, the instrument builds up (nearly) arbitrary three-dimensional structures at the micron to sub-micron scale. Take a look at the pictures in their newsletter and in their company booklet.

Photonic wire bonding

Karlsruhe Institute of Technology has demonstrated photonic wire bonding between two SOI chips. They have demonstrated an aggregate data transmission rate of 5.25 Tbit/s over one photonic wire. Assuming a linear wire bond pitch of 5 microns, they conclude that a transmission rate of 1 Pbit/s/mm from a chip is within reach.

The photonic wire bonds are manufactured by two-photon lithography in SU-8 resist. One can easily envision taking this technology into manufacturing. It should enable very high speed chip-chip communication.

For details, see arXiv:1111.0651v1.