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Physics

A polariton filter turns ordinary laser light into quantum light

Nature Materials paper Tuesday, 19 February 2019

Artist’s impression of the polaritonic photon conversion platform. Laser photons enter through the top mirror and leave through the bottom mirror exhibiting quantum ‘granularity’ – after interacting with the semiconductor layer. Image: Andrew Wood

An international team of researchers led out of Macquarie University has demonstrated a new approach for converting ordinary laser light into genuine quantum light.

Their approach uses nanometre-thick films made of gallium arsenide, which is a semiconductor material widely used in solar cells. They sandwich the thin films between two mirrors to manipulate the incoming photons.

The photons interact with electron-hole pairs in the semiconductor, forming new chimeric particles called polaritons that carry properties from both the photons and the electron-hole pairs. The polaritons decay after a few picoseconds, and the photons they release exhibit distinct quantum signatures.

The teams’ research was published overnight in the journal Nature Materials.

[Read more…] about A polariton filter turns ordinary laser light into quantum light

Reinventing the laser

High-power diamond lasers, invented at Macquarie University, Eureka finalist

High-power lasers have many potential applications: from medical imaging to manufacturing, shooting down drones or space junk, or powering deep space probes. But current laser technologies overheat at high power.

Rich Mildren and his team have developed a technique to make diamond lasers that, in theory, have extraordinary power range. Five years ago, their lasers were just a few watts in power. Now they’ve reached 400 watts, close to the limit for comparable conventional lasers.

Their calculations suggest that their diamond laser technology could handle over a thousand times the current power. They’ve also shown that they can use diamond to focus multiple laser beams into a single beam. And they can create almost any frequency of light.

Diamond is an outstanding optical material and exceptionally good at dissipating heat. But it’s not very good at generating a laser beam as its dense structure makes it difficult to introduce the impurity additives normally needed to amplify light. Until now.

[Read more…] about Reinventing the laser

Revealing the dark side – in Tasmania this week

Tamara Davis - 2009 FellowWhat we see in the night sky is only five per cent of the Universe. So what’s the other 95 per cent of the Universe made of – a young physicist has the answers across Tasmania this week.

One of Australia’s leading young physicists will reveal the dark secrets of the Universe in Tasmania this week with a series of school and public talks in Burnie, Launceston, Devonport and Hobart.

Dr Tamara Davis is a L’Oréal Australia Fellow, the 2011 national Women in Physics lecturer, an astrophysicist at the Universities of Queensland and Copenhagen, and good talent. [Read more…] about Revealing the dark side – in Tasmania this week

Born from astronomy…Creating a future with astronomy

In 1768 the British Admiralty sent Captain James Cook to the Pacific to monitor the transit of the planet Venus across the Sun. On his way home to England, Cook mapped Australia’s east coast, and claimed New South Wales.

For about 40,000 years before that, the indigenous peoples of Australia had been developing remarkably sophisticated explanations of the workings of the Southern Sky. [Read more…] about Born from astronomy…Creating a future with astronomy