Polymer lasers without mirrors
The waveguide structure was created by pouring a mixture of copolymer solution and molecular laser dye into a mould situated on top of a silicon wafer. The solution was allowed to solidify over 12 hou...
Read article: Nuclear physics with lasers
Nuclear physics with lasers
About 20 years ago Toshi Tajima and John Dawson, then at the University of California at Los Angeles, suggested that laser-produced plasmas could be used to accelerate particles to high energies. The ...
Electrons trapped by laser beam
The experiment was carried out inside a vacuum chamber filled with a low density nitrogen or argon gas. A wave plate – in the form of a small circular piece of material – was inserted into...
Water transfers energy at ultrafast rate
As a water molecule is excited by the laser pulse, it can only drop back to a less excited state by releasing the excess energy. This energy causes the O-H bonds to stretch and vibrate. As the bonds v...
Ultrafast X-rays watch matter melt
The germanium sample was bombarded with powerful laser pulses to excite the electrons and cause thermal melting. In this process, unlike normal melting, the metallic crystal goes from a cold solid to ...
Reflections on the life of a laser pioneer
Charles Townes has written a biography – but it is not clear if it is his own or that of the laser. The laser is now such a feature of our everyday life that the remarkable story of its birth ne...
Bi-directional laser breakthrough
Light is emitted from a quantum cascade laser when an electron falls from an excited energy level in a quantum well to a lower level. The quantum wells are defined by alternating layers of semiconduct...
Chemical physicist wins Nobel chemistry prize
Prior to Zewail’s work chemists had thought that chemical reactions occurred on the same time scale as molecular vibrations — that is, on the femtosecond scale. In the late 1980s, Zewail d...
Top quark and Bell’s inequalities top PhysicsWeb Nobel poll
Every year the Foundation asks 3000 physicists to nominate individuals for the prize, and compiles a short-list of 250 candidates. These names are then whittled down to a list of 30, from which the wi...
Blue lasers look up
Most semiconductor lasers emit light from the edge of the active laser region. However, in the VSCEL geometry light is emitted from the top of the device. This can reduce the threshold current needed ...
