Everyone has heard about lasers. But do you know what people used for deep space communication and radio astronomy before lasers were invented? Masers – microwave version of lasers. The problem with masers is that they have to be cooled to extremely low temperatures to work. However, not scientists from UCL and Imperial College London have created the world’s first continuous room-temperature solid-state maser.
Synthetic diamond in a sapphire ring made for a good maser, which can work continuously at room temperature. Image credit: Jonathan Breeze and Chris Kay, UCL
Masers (microwave amplification by stimulated emission of radiation), invented in 1954, would be useful in a variety of applications in medical and security fields. However, they are not very practical, because they must be cooled to temperatures close to absolute zero (-273°C) to function. Now scientists embedded a diamond in a ring of sapphire to create world’s first continuous room-temperature solid-state maser. This is a huge breakthrough, which could lead to improvements in communication technologies, space exploration equipment, magnetic resonance imaging – it could even lead to quantum computers.
It is not the first time that masers are working in room temperature. Scientists have managed to make a maser work in room temperature using organic molecule pentacene back in 2012. However, at that time the device was only producing short bursts of radiation that lasted less than one thousandth of a second. Furthermore – if they somehow managed to make it work continuously, the crystal would have melted. That is why now scientists used an artificially produced diamond. They shot the diamond crystal with high energy electron beams that produced vacancies in the carbon structure. Because this was done in a nitrogen-rich environment, these vacancies were paired up with nitrogen atoms forming a type of defect known as a nitrogen-vacancy (NV) centre. Then the diamond was places in a sapphire ring to concentrate the microwave energy.
When illuminated with green laser, this maser worked continuously at room temperatures. Dr Jonathan Breeze, leader of the study, said: “This breakthrough paves the way for the widespread adoption of masers and opens the door for a wide array of applications that we are keen to explore. Hopefully, the maser will now enjoy as much success as the laser”.
Of course, maser technology has long ways to go to reach success of the laser. But there is a variety of fields that could benefit from this technology. Scientists say that their maser would be useful everywhere, where sensitive detection of microwave radiation is important.