For the first time, scientists at Harvard University have converted a laser into a radio, thereby transmitting music wirelessly . Conventional radios convert sound into electromagnetic waves, which are then transmitted wirelessly through the air using a radio signal. Antennas then receive the analog or digital signals to convert them back into sound, which is then reproduced via the loudspeakers.
Scientists at Harvard University have successfully transmitted a radio signal using a laser frequency comb. According to the scientists, the new, already patented technology can be a faster alternative to the WLAN currently in use.
In the study now published in the journal Proceedings of the National Academy of Sciences , a team of scientists around Marco Piccardo shows that radio signals can also be transmitted using a laser. The most important component of the system is a so-called laser frequency comb, which emits light in clearly separated spectral lines. The independently working tines of the laser frequency comb each send out a data signal.
Receive and send possible:
Piccardo and his colleagues explain that “it has been shown that a laser microwave is capable of producing information-carrying signals and emitting them wirelessly.” In another experiment, the scientists also showed that a change in the microwave signal at the laser frequency comb caused it also allows information to be received.
In the future, the foundations that have now been created could enable the development of new hybrid electronic-photonic devices, which should enable new speed records in wireless data transmission. According to the scientists, the data rates can significantly exceed current WLAN standards. The technology, which has already been patented, is now to be further developed in order to create concrete applications for everyday use.
Put an end to the tangle of cables: music from MP3 players, cell phones or PCs can be easily transmitted to speakers and stereo systems. This makes operation more convenient. These technologies participate.
Three radio technologies:
It’s actually great that there are technical standards for wireless music playback. This allows devices from different manufacturers to be combined. For example, Apple devices can send their music via WiFi to JBL Airplay speakers. And when it comes to wireless transmission via Bluetooth, it doesn’t matter whether the cell phone was built by Nokia or Samsung.
Nevertheless: Which radio technology is best suited in which case depends on many factors. If the music collection is to be played on a mobile device and only to be heard in one room, Bluetooth and Airplay are ideal – wireless transmission in the DLNA network standard is often too complex.
On the other hand, when it comes to the highest possible sound quality, airplay and DLNA are particularly suitable – Bluetooth cannot keep up with both in this regard.
Until now, laser frequency combs have been used almost exclusively for photonic applications. However, scientists at Harvard University have discovered that laser frequency combs, which are now so small that they fit on a microchip, can generate oscillations in the same frequency range that is also used by radio and cell phone systems.
In order to prove the assumption experimentally, the scientists encoded data into the oscillations of the emitted light from a laser frequency comb. A photodetector then converted these signals into microwaves, which could be emitted as a radio signal via an antenna. The song “Volare” by Dean Martin, which was transmitted by laser frequency comb, was successfully received via a conventional radio antenna and played back normally.
Bluetooth: Play music from cell phones and MP3 players:
Numerous cell phones and some MP3 players, for example from Sony, Philips, Creative and Apple, can transmit music via Bluetooth radio. This can usually cover distances of up to ten meters.
For playback, there are cheap speakers from PC and cell phone accessories, such as from Creative, Logitech, Hama and Altec Lansing (from 50 euros). But also higher-quality docking stations like the JBL OnBeat Xtreme (around 400 euros) play music via Bluetooth.
Stereo systems can receive the radio signals with a Bluetooth adapter such as the Belkin Music Receiver (around 30 euros). It is connected to a free stereo input.
Airplay: music radio for Apple and iTunes users
With Airplay, the devices either establish a direct radio connection with each other or they use an existing wireless network (WLAN). IPod touch, iPhone, iPad and computers with iTunes can be used as channels .
Suitable receivers are the Apple TV network player , the Airport Express radio station and appropriately equipped docking speakers such as the JBL OnAir wireless (around 350 euros) and the B&W Zeppelin Air (600 euros). In addition, some AV receivers, Blu-ray and mini CD systems from Denon, Sony, Pioneer, Marantz and Harman Kardon can receive music via Airplay.
Advantages: As with Bluetooth radio, the music can be selected directly on the iPod touch or iPhone. However, the sound is better – the quality of the played file is preserved. And the selected track can be heard on several players at the same time.
Disadvantages: WLAN radio empties the battery a little faster than Bluetooth. A WLAN router is required for music in several rooms.
DLNA with smartphone: PC music in the whole apartment
If the music selection on the cell phone or MP3 player is too small, you can save your tracks in your home network. A PC or other device with a DLNA server program then works as the transmitter, for example a network hard disk. The radio comes from the WLAN router. Network players, AV receivers and Internet radios that support the DLNA or UPnP standard are suitable as receivers.
There are two options for operation: either on the receiver with buttons and infrared remote control – or via smartphone app . To do this, a so-called DLNA app must be installed on the mobile phone, which controls the server in the network. The program usually also ensures that large music archives can be conveniently searched.
Advantages: The sound is as good as with Airplay – or even better if high-resolution music files from special providers are played on the network. In addition, several recipients can use the archive and play different titles at the same time.
Disadvantage: The setup and operation of the music network is more complicated than with the other two radio variants.