| Home / lib / E_Engineering / EO_Optical devices / | ||
Webb C.E., Jones J.D.C. (eds.) Handbook of Laser Technology, vol.3.. Applications (IoP, 2004)(K)(600dpi)(T)(1179s)(ISBN 0750309601)_EO_.djvu |
|
Size 76.9Mb Date Mar 15, 2006 |
[184] Kettling U, Koltermann A, Schwille P and Eigen M 1998 Real-time enzyme kinetics monitored by dual-color fluorescence
cross-correlation spectroscopy PNAS 95 1416-20
[185] Kinjo M, Nishimura G, Koyama T, Mets U and Rigler R 1998 Single-molecule analysis of restriction DNA fragments using
fluorescence correlation spectroscopy Anal...
D3.5.2.1.1 Recognize the importance of protective eyewear
A dramatic account of a laser injury was given by Dr David Decker who was himself the victim [1]...
He heard what sounded like a snap in his left
eye and saw an immediate bright after-image which lasted for about 20 minutes...
On examination of the
fibre it was seen that the aiming beam emerged from both the distal tip and a hole in the metal sheath some
5 mm from the end...
Diffuse radiation from a Lambertian reflector is not usually a problem with all lasers up to and including
class 3B...
There is a range of simple
visual checks that may be undertaken prior to clinical use of the laser and more complex measurements that
may be undertaken by suitably qualified personnel at longer intervals...
In response
to this evidence it examines the validity of the maximum permissible exposure (MPE) tables and, if necessary,
recommends changes...
D3.5.6.1 Laser protection adviser
So, it is recommended that the employer should appoint a laser protection advisor (LPA) who will have
delegated responsibility for advising the Chief Executive and the board, staff and the public on laser radiation
matters...
It should also be noted that if an
organization carries out equipment modification then this may result in the transfer of liability from the
manufacturer to the organization...
This is an extremely useful parameter in deciding
the area in which precautions must be taken...
D3.5.9 Anaesthetics
Many class 4 surgical lasers are readily capable of setting fire to materials in the clinical environment...
This utilizes jet ventilation and is not
only preferable from a laser safety point of view, but also provides the surgeon with improved access to the
treatment site...
The irony is that this has been achieved with a very crude optical
signalling system that does not, as yet, utilize any of the sophisticated modulation techniques developed over
100 years of radio communication...
Note that a drop of 3 dB in modulated optical power (that is, a factor of two) corresponds to a reduction of 6 dB in the modulated
electrical signal in the receiver...
In order to reduce the linewidth further, and with it the effect of the fibre chromatic dispersion, a
grating can be etched into the semiconductor material close enough to the optical cavity to interact with the
laser electromagnetic fields...
Finally, in the first decade of the new century, the growth of demand for electronic communication, in
particular through the expansion of the use of the Internet, has seen a new battle break out between optical
fibre and copper wire for data communication within and between office complexes and for the final link
to the private domestic subscriber...
Advantages
Disadvantages
Low attenuation and low dispersion possible,
allowing repeater spacing to be high (> 100 km)
at the highest bit-rates (> 1 Gb s)...
An important feature that distinguishes optical frequency communication from radio and microwave
systems is the quantum noise generated in the photodiode detector...
They normally use quantum-
well laser sources emitting a few tenths of a watt and can carry data at bit rates up to 1 Gb s over distances
of a few kilometres...
| © 2007 eKnigu | ||