1. JAIPUR NATIONAL UNIVERSITY
SCHOOL PHARMACEUTICAL SCIENCES
Laser
(Light Amplification by Stimulated Emission of
Radiation)
vineeGupta
M.Pharma 2ndsem
Pharmecutics
JNU, jaipur

2. The LASER beam was invented by the
physicist MAIMAN in 1960
 One of the most influential
technological achievements of the 20th
century
Lasers are basically excited light
waves

3. STIMULATED EMISSION (2)
Incident
photon Incident
photon
Emitted
photon
Excited
electron
Unexcited
electron
Before emission After emission

4. CHARACTERISTICS OF LASER LIGHT
MONOCHROMATIC
DIRECTIONAL
COHERENT
The combination of these three properties makes laser
light focus 100 times better than ordinary light

5. INVERTED POPULATION
When a sizable population of electrons resides in upper levels, this
condition is called a "population inversion“
In order to obtain the coherent light from stimulated
emission, two conditions must be satisfied:
1. The atoms must be excited to the higher state. That is, an
inverted population is needed, one in which more atoms
are in the upper state than in the lower one, so that
emission of photons will dominate over absorption.
Unexcited system
1E
2E
3E
Excited system
1E
2E
3E

6. METASTABLE STATE
2. The higher state must be a metastable state – a state in
which the electrons remain longer than usual so that the
transition to the lower state occurs by stimulated emission
rather than spontaneously.
Metastable state
Photon of energy 12 EE 
1E
2E
3E
Metastable system
1E
2E
3E
Stimulated emission
Incident photon
Emitted photon

7. 7
INCANDESCENT VS. LASER LIGHT
1. Many wavelengths
2. Multidirectional
3. Incoherent
1. Monochromatic
2. Directional
3. Coherent

8. Radio
Long WavelengthShort Wavelength
Gamma Ray X-ray Ultraviolet Infrared Microwaves
Visible
ELECTROMAGNETIC SPECTRUM
Lasers operate in the ultraviolet, visible, and infrared.
Radio

9. LASER SPECTRUM
10-13 10-12 10-11 10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 1 10 102
LASERS
200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 10600
Ultraviolet Visible Near Infrared Far Infrared
Gamma Rays X-Rays Ultra- Visible Infrared Micro- Radar TV Radio
violet waves waves waves waves
Wavelength (m)
Wavelength (nm)
Nd:YAG
1064
GaAs
905
HeNe
633
Ar
488/515
CO2
10600
XeCl
308
KrF
248
2w
Nd:YAG
532
Retinal Hazard Region
ArF
193
Communication
Diode
1550
Ruby
694
Laser-Professionals.com
Alexandrite
755

10. 10
LASER OUTPUT
Continuous Output (CW) Pulsed Output (P)
watt (W) - Unit of power or radiant flux (1 watt = 1 joule per second).
Joule (J) - A unit of energy
Energy (Q) The capacity for doing work. Energy content is commonly used to characterize the
output from pulsed lasers and is generally expressed in Joules (J).
Irradiance (E) - Power per unit area, expressed in watts per square centimeter.
Energy(Watts)
Time
Energy(Joules)
Time

11.  LASER can be considered to be a form of light
amplifier,
 behave according to the basic laws of light,
characteristics:
- travels in straight lines with a constant velocity in space;
- it can be located inside the electromagnetic spectrum acc. to its
wavelength or frequency;
- it present a particular chromatic purity;
- can be transmitted;
- can be reflected;
- can be refracted;
- can be absorbed;
- it has the capacity of transmitting energy without loss through the
air
- the LASER can be used both as unitary impulses and under
continuous form.

12. LASER COMPONENTS
ACTIVE MEDIUM
Solid (Crystal)
Gas
Semiconductor (Diode)
Liquid (Dye)
EXCITATION
MECHANISM
Optical
Electrical
Chemical
OPTICAL
RESONATOR
HR Mirror and
Output Coupler
The Active Medium contains atoms which can emit
light by stimulated emission.
The Excitation Mechanism is a source of energy to
excite the atoms to the proper energy state.
The Optical Resonator reflects the laser beam through
the active medium for amplification.
High Reflectance
Mirror (HR)
Output Coupler
Mirror (OC)
Active
Medium
Output
Beam
Excitation
Mechanism
Optical Resonator

13.  the beam of light is reflected back and forth along
the central tube, until the waves of light become
coherent.

14. MECHANISM OF LASER EMISSION
ABSORPTION
E1
E2

15. SPONTANEOUS EMISSION

16. STIMULATED EMISSION

17. CLASSIFICATION OF LASER ACC. TO
PRODUCTION TECHNIQUE
1. Optically Pumped Solid-State Lasers
I. Ruby Laser
II. Rare Earth Ion Lasers
III. Nd: YAG Lasers.
IV. Nd: Glass Lasers
V. Tunable Solid-State lasers

18. 2 Liquid (Dye) Lasers
3 Gas Lasers
4 Semiconductor Lasers
5 Free Electron Lasers
6 X-ray Lasers, and
7 Chemical Lasers

19. TYPES OF MEDICAL LASERS, ACCORDING
THE INTENSITY OF EMISSION
a) Power LASER –
 has a strong emission
 only used in surgery; used to cut, coagulate and
evaporate tissues
 they can replace the scalpel of the surgeon
 this are ,,Hot laser’’, it deliver power up to thousands of
watts, for removal of unhealthy tissue without damaging the
healthy tissue that surrounds it.
b) Mild LASER –
 medium emission
 is used for treatment of deeper tissues
c) Soft LASER –
 weak emission
 acts only at the surface (dermathology)

20. LASER HAZARD CLASSES
Lasers are classified according to the level of laser
radiation that is accessible during normal operation.

21. CLASS 1 • Safe during normal use
• Incapable of causing injury
• Low power or enclosed beam
CLASS I Laser Product
Label not required
May be higher class during
maintenance or service
Nd:YAG Laser Marker

22. CLASS 2
CLASS II LASER PRODUCT
Laser Radiation
Do Not Stare Into Beam
Helium Neon Laser
1 milliwatt max/cw
• Staring into beam is eye hazard
• Eye protected by aversion response
• Visible lasers only
• CW maximum power 1 mW
Laser Scanners

23. CLASS 3R (Formerly 3a)
Small Beam
Expanded Beam
CLASS IIIa Laser Product
LASER RADIATION-
AVOID DIRECT EYE EXPOSURE
ND:YAG 532nm
5 milliwatts max/CW
• Aversion response may not provide
adequate eye protection
• CDRH(Center for Devices and Radiological Health )
includes visible lasers only
• ANSI includes invisible lasers
• CW maximum power (visible) 5 mW
Laser Pointers
CLASS IIIa LASER PRODUCT
Laser Radiation-
Do Not Stare Into Beam or View
Directly With Optical Instruments
Helium Neon Laser
5 milliwatt max/cw

24. CLASS 3B
• Direct exposure to beam is eye hazard
• Visible or invisible
• CW maximum power 500 mW
CLASS IIIb Laser Product
LASER RADIATION-
AVOID DIRECT EXPOSURE TO BEAM
2w ND:YAG Wavelength: 532 nm
Output Power 80 mW
DPSS Laser with cover removed

25. CLASS 4
CLASS IV Laser Product
VISIBLE LASER RADIATION-
AVOID EYE OR SKIN EXPOSURE TO
DIRECT OR SCATTERED RADIATION
2w Nd:YAG
Wavelength: 532 nm
Output Power 20 W
• Exposure to direct beam and scattered
light is eye and skin hazard
• Visible or invisible
• CW power >0.5 W
• Fire hazard

26. Laser-Professionals.com
M is for magnification.
A class 1M laser is class 1 unless magnifying optics are used.
A class 2M laser is class 2 unless magnifying optics are used.
M classes usually apply to expanded or diverging beams.
CLASS 1M & 2M
Condition 2
Diverging Beam
Condition 1
Expanded Beam

27. Class 1 Incapable of causing injury during normal operation
Class 1M Incapable of causing injury during normal operation
unless collecting optics are used
Class 2 Visible lasers incapable of causing injury in 0.25 s.
Class 2M Visible lasers incapable of causing injury in 0.25 s
unless collecting optics are used
Class 3R Marginally unsafe for intrabeam viewing; up to 5 times the
class 2 limit for visible lasers or 5 times the class 1 limit
for invisible lasers
Class 3B Eye hazard for intrabeam viewing, usually not an eye
hazard for diffuse viewing
Class 4 Eye and skin hazard for both direct and scattered exposure
LASER CLASSIFICATION SUMMARY
Laser-Professionals.com

28.  The Federal Laser Product Performance Standard (FLPPS)
of the Center for Devices and Radiological Health (CDRH)
This is federal law and applies to the manufacture of lasers.
 The American National Standard for Safe Use of Lasers (ANSI
Z136.1) This is a VOLUNTARY Standard that applies to the use of
lasers.
“recognized by” :
The Occupational Safety and Health Administration (OSHA)
 IEC 60825 International Standard
LASER SAFETY STANDARDS

29. MORE RECENTLY HAVE BEEN ADOPTED
THE TERMS OF:
Low Level Laser Therapy (LLLT),
Low Intensity Laser Therapy (LILT).
LLLT devices are typically delivering
10mW -200mW (0.2  0.01 Watts).

30. LLLT WHEN APPLIED
TO THE BODY TISSUES
The generation of heat perturb local
electron orbits  and the result/
mechanisms on the cell membrane
Initiate chemical change,
Disrupt molecular bonds and
Produce free radicals.

31. TRATAMENT BY LLLT
 LLLT offer superior healing and pain relieving effects
, especially in the early stages of acute injuries, and for
chronic problems.
 LLLT is a universal method of treating muscle, tendon,
ligament, connective tissue, bone and skin tissue with
one simple piece of equipment, however, the best
results are achieved when it is used to complement
other treatment modalities!
 Importantly for athletes, LLLT is a non-invasive,
drug-free modality that can be applied on competition
day without risking disqualification by drug testing!

32. HOW DOES LASER WORK?
 The LASER effect at the cellular level, in vivo
situation, is not complete and it is not very well know
,
 studies are conducted for the research of all this
effects, and it is far away to be completed.

33. DOSE CALCULATIONS
 Energy Density is measured in units of Joules
per square centimeter (J/cm2).
 a lot of apparatus offer '’on board'’ calculations
of this dose
 operator to make some simple calculations
based on several considerations:
 output power (Watts)
 irradiation area (cm2)
 time (seconds)

34. GENERALITY
 Most authorities suggest that the ENERGY DENSITY per
TREATMENT SESSION should generally reduce in the
range of 0.1 - 12.0 J/cm2 despite the fact that there
are some recommendations which go up to 30 J/cm2.
 maximal dose of 4 J/cm2 should not be
exceeded.
 Lower doses should be applied to the more acute
lesions which would appear to be more energy
sensitive.
 Treatment time between 4 and 12 minutes.

35. FEDERAL SAFETY REQUIREMENTS FOR CLASS 1 LASER
SYSTEMS WITH ENCLOSED CLASS 3b AND 4 LASERS
Protective Housing
prevents access to laser radiation above safe level.
Safety Interlocks
terminate laser beam if protective housing in opened.
Only authorized personnel may operate laser with interlocks defeated.
Warning Labels
alert personnel if opening the housing might expose a laser
hazard.
Viewing Windows and Optics
limit laser and collateral radiation to safe levels.

36. DEFINITION OF MPE
Maximum
Permissible
Exposure
The level of laser light to which a person
may be exposed without risk of injury.

37. SUGGESTED SOP FORMAT
1. Introduction – Description of laser
Type and wavelength; Intended application & Location
Average power or energy per pulse
Pulse duration and repetition rate for pulsed lasers
2. Hazards – List all hazards associated with laser
Eye and skin hazards from direct and diffuse exposures
Electrical hazards
Laser generated air contaminants
Other recognized hazards
3. Control Measures – List control measures for each hazard
Eyewear requirement, include wavelength and OD
Description of controlled area and entry controls
Reference to equipment manual
Alignment procedures (or guidelines)
4. Authorized Personnel
5. Emergency Procedures

38. CONTRAINDICATIONS OF LASER
THERAPY ARE
 Pregnancy  treatment over the pregnant uterus
could affect rapidly dividing cells,
 Patients with chronic pain have reported increased
tiredness for a brief period, and long-standing pain 
conditions may transiently increase.
 Areas of impaired sensation.
 Infections  increase the risk of spreading the
infection,
 Hemophilia,

39. 39
CONTROL MEASURES
Engineering Controls
 Interlocks
 Enclosed beam
Administrative Controls
 Standard Operating Procedures (SOPs)
 Training
Personnel Protective Equipment (PPE)
 Eye protection

40. CDRH CLASS WARNING LABELS
CLASS II LASER PRODUCT
Laser Radiation
Do Not Stare Into Beam
Helium Neon Laser
1 milliwatt max/cw
CLASS IV Laser Product
VISIBLE LASER RADIATION-
AVOID EYE OR SKIN EXPOSURE TO
DIRECT OR SCATTERED RADIATION
Argon Ion
Wavelength: 488/514 nm
Output Power 5 W
Class II
Class IIIa with expanded beam
Class IIIa with small beam
Class IIIb
Class IV

41. INTERNATIONAL LASER
WARNING LABELS
Symbol and Border: Black
Background: Yellow
Legend and Border: Black
Background: Yellow
INVISIBLE LASER RADIATION
AVOID EYE OR SKIN EXPOSURE
TO DIRECT OR SCATTERED RADIATION
CLASS 4 LASER PRODUCT
WAVELENGTH 10,600 nm
MAX LASER POWER 200 W
EN60825-1 1998

42. USES
 In medicine
 to break up gallstones and kidney stones,
 to weld broken tissue (e.g. detached retina)
 to destroy cancerous and precancerous cells; at the same time,
the heat seal off capillaries,
 to remove plaque clogging human arteries.
 used to measure blood cell diameter
 fibre-optic laser catheter is in the treatment of bleeding
ulcers.
 can photocoagulate blood
 can also be used for dental treatment

43. In industry
 to drill tiny holes in hard materials,
 for welding and machining,
 for lining up equipment precisely, especially in inaccessible
places

44.  In everyday life
 to be used as bar-code readers,
 to be used in compact disc players,
 to produce short pulses of light used in digital
communications,
 to produce holograms.

45. HOLOGRAPHY
 Holography is the production of holograms by the use of
laser.
 A hologram is a 3D image recorded in a special
photographic plate.
 The image appears to float in space and to move when
the viewer moves.

46. RESEARCH
 used to measure the speed of light in a laboratory

47. CLASS 4 LASER
ND:YAG 1064 nm
100 Watts Max. Average Power
VISIBLE and/ or INVISIBLE LASER
RADIATION-AVOID EYE OR SKIN
EXPOSURE TO DIRECT OR
SCATTERED RADIATION.
Controlled Area Warning Sign

48. LABORATORY DOOR INTERLOCK

49. ENTRYWAY WARNING LIGHTS

50. Photos courtesy of
LASER PROTECTIVE BARRIERS

51. CURBS ON OPTICAL TABLE

52. BEAM CONTROL

53. LASER SAFETY EYEWEAR

54. EYEWEAR LABELS
All eyewear must be labeled with wavelength and optical density.

55. The person operating the laser
always has the primary
responsibility for all hazards
associated with laser use.
WHO HAS PRIMARY RESPONSIBLITY
FOR LASER SAFETY ANY TIME A CLASS
3B OR CLASS 4 LASER IS OPERATED?

56. CONCLUSION
 Laser communication in space has long been a goal for
NASA because it would enable data transmission rates
that are 10 to 1,000 times higher than traditional radio
waves.
 While lasers and radio transmissions both travel at light-
speed, lasers can pack more data. It's similar to moving
from a dial-up Internet connection to broadband.
Astronomers could use lasers like very accurate rulers to
measure the movement of planets with unprecedented
precision.
With microwaves, we're limited to numbers like a meter
or two in distance, whereas [lasers have] a potential for
getting down into well beyond the centimeter range.

57. THANK YOU