editorial Master of electrons and photons Nikola Tesla is known for his work on alternating current power systems, induction motors and wireless transmission but he is also an unsung hero of research into X-rays and light sources. Next month, on 10 July to be exact, would at ordinary pressures. Tesla had already have been Nikola Tesla’s 159th birthday. developed high-frequency fluorescent bulbs The surname of the Serbian-American in the early 1890s. inventor extraordinaire typically kindles Tesla’s name may have edged towards thoughts of polyphase alternating obscurity after his death but in recent current power systems, high-voltages years he has experienced a resurgence in and ‘lightning’, wireless telegraphy or the appreciation and popularity. This is partly unit of magnetic field strength, which because the importance and avant-garde was named in his honour 17 years after nature of his work still has significance his death in 1943. Less well known is that after a century. Also, some of his claims and Tesla also made important contributions to ideas lend themselves well to science fiction photonics, related to the understanding of (for example, mechanical oscillators for electromagnetic wave propagation, X-ray demolishing buildings using resonance, and sources and imaging techniques, fluorescent ‘death rays’ based on particle acceleration). tubes, phosphorescence and incandescence. He is also well known for expressing Many of Tesla’s ideas were ahead of their that he toiled for humanity rather than time. In 1898 he unveiled a ‘teleautomaton’ financial gain (in particular with regards aquatic vehicle (www.tfcbooks.com/ to ‘free’ energy) and for this the internet patents/0613809.htm) at an exhibition at now loves him. A music video describing 1,2 Madison Square Garden that seemed to TESLA MUSEUM NIKOLA his achievements and attitudes has over respond to commands to move, stop or turn. 31 million views to date (www.youtube. Perhaps equally unbelievable at the time image of a camera screw, weeks prior to com/watch?v=gJ1Mz7kGVf0). A 2012 was that Tesla had installed a battery, motor Röntgen’s famous announcement, while crowd-funding internet campaign raised and the necessary circuitry in the boat to photographing Mark Twain using a Geissler US$1.4 million to purchase the property of radio-control its movement. A submarine tube (a predecessor to the Crookes tube). Tesla’s former laboratory in Wardenclyffe, version was later demonstrated but Tesla Following Röntgen’s discovery, Tesla made Shoreham, New York, for preservation. apparently received little commercial or specialized equipment for X-ray sources A similar effort in 2014 raised a further military interest in either version. More than and many of his high-quality images even US$518,000 in one month towards building a century later, with the advent of drone impressing Röntgen4. Tesla described his a museum at the site. technology, Tesla is now being called the work on this topic in a series of articles in For those wishing to know more about father of unmanned vehicle technology3. Electrical Review in 1886 and pointed out this astonishing figure there are excellent clinical applications of X-rays4. books documenting Tesla’s life1,2 and his Many of Tesla’s ideas were Dr Branimir Jovanovic, Director of lectures and patents can be read online5. the Nikola Tesla Museum (http://www. The Nikola Tesla Museum in Belgrade ahead of their time. tesla-museum.org/meni_en.htm) in has a large photo collection, original Belgrade, Serbia, told Nature Photonics documents, Tesla’s ashes in a spherical urn Tesla contributed to a number of other that from early 1896 Tesla was producing (Tesla’s favourite geometry) and a replica fields not automatically associated with X-rays using apparatus he had designed. of the radio-controlled boat. There are also his name, such as his work on gas turbines These involved his oscillating current important sites in Colorado Springs where and aircraft vertical take-off and landing transformer using the highest possible Tesla worked on wireless telegraphy — it schemes, which he patented in 1928. voltages at that time as well as specialized is there that the famous multiple exposure Perhaps more relevant to the readership tubes. Jovanovic also explained that Tesla picture of Tesla casually reading a book with of Nature Photonics is the fact that Tesla may have discovered X-ray reflection ‘lightning’ about him arcing across 7 million didn’t only work with low-frequency and was among the first to propose metal volts of potential was captured. On the electromagnetism but also with higher- shielding for operator safety. internet, you can even buy a Tesla turbine frequency phenomena. According to Jovanovic, Tesla’s and other kits. ❐ The great German physicist Wilhelm contribution to light generation is more Röntgen was the first to systematically study timely. In April 1887 Tesla Electric Light References X-rays and is credited with their discovery & Manufacturing was formed1. Tesla’s 1. Seifer, M. J. Wizard: The Life and Times of Nikola Tesla (Citadel Press, 2001). in 1895. However, others experimenting lectures on high-frequency of the early 2. Carlson, W. B. Tesla: Inventor of the Electrical Age (Princeton with Crookes tubes had observed some 1890s, including On Light and Other High Univ. Press, 2013). of the effects of X-rays. In 1894 Tesla Frequency Phenomena, are available online5. 3. Weber, A. Nikola Tesla: Father of Unmanned Vehicle Technology. reportedly began investigating X-rays He conducted research on the incandescence Assembly (26 April 2010); http://go.nature.com/F6SXjJ 4 4. Hrabak, M. et al. RadioGraphics 28, 1189–1192 (2008). after noticing damaged film . Tesla may and phosphorescence of solids and rarefied 5. Twenty-first Century Books http://www.tfcbooks.com/ even have inadvertently made an X-ray gases as well as luminosity from gases tesla/1893-02-24.htm (2013). NATURE PHOTONICS | VOL 9 | JUNE 2015 | www.nature.com/naturephotonics 345 © 2015 Macmillan Publishers Limited. All rights reserved.