Encyclopedia Of Laser Physics Technology: Essay On Characteristics, Types, And Safety Measures.

Introduction to lasers

Discuss About The Encyclopedia Of Laser Physics Technology.

The LASER is an acronym when expanded means Light Amplification by Stimulated Emission of Radiation. Through the process of optical amplification, electromagnetic radiation is emitted by Laser. The principle upon which the Laser is based is called stimulated emission of photons. Laser characteristics are dependent on the wavelength of the laser beam. Lasers are monochromatic, coherent, collimated. Monochromatic means the laser light consists of a single wavelength of light rather than multiple wavelengths; in a laser beam, the wavelengths remain in phase and the waves are in troughs and crest and remain parallel to each other (Menzel 2013). Laser light is collimated and remains very narrow and the laser light travels in the same direction. Due to this property, immense is produced at the place where the laser remains concentrated. A laser consists of an optical cavity, energy source or pumping system, and a proper lasing medium. There are different types of lasers and they are mainly classified based on the lasing management in the lasing cavity. solid state lasers are the ones which use the crystalline lasing material like, neodymium lasers or ruby; gas lasers are the ones that use the gas mixture like, helium-neon and carbon dioxide (Nazemisalman, Farsadegh and Sokhansanj 2015). Diode/semiconductor lasers that use the p-type and n-type semiconducting materials; dye/liquid lasers are the ones that use organic dye suspended in a liquid medium. Excimer lasers are the one that uses the mixture of fluorine and chlorine along with inert gases like xenon and krypton and argon. Lasers are classified based on the types like- class 1, 1C, 1M, 2, 2M, 3R, 3B, 4 (Meschede 2017). This study is based on laser safety and the associated hazards, risks and control measures. 

The products where the class 1 and 1M lasers are used are laser printers, CD players and DVD players. The product where the class 2 and 2M is used is the barcode scanners. The class 3R lasers are used in products like laser pointers. The class 3B lasers are used in products like laser light show projectors, industrial lasers and research lasers (Warwick.ac.uk 2018).

The class 1 and 1M are the lasers which are considered as non-hazardous. However, it is important to note that the level if hazard increases when viewed with telescopes, binoculars, magnifiers and other optical aids. The class 2 and 2M lasers are lasers in which the hazard increases when viewed for longer periods of time and the level of hazard also increases when viewed with the optical aids. The class 3R lasers are the lasers that depend on the beam area and the power. This can be hazardous when viewed directly for a long period of time and also when stared directly at the beam of lasers without any eye aid. However, the risk of injury can be more when viewed along with optical aids. The class 3 B is the class of laser which has immediate issue of skin hazard from the direct beam and also has the immediate eye hazard when the beam is viewed directly. The Class 4 lasers are the lasers which cause the immediate skin hazard and also has the eye hazard due to either the reflected or direct beam of light. it can also present with a fire hazard. The class 4 lasers are found in products like laser light show projectors, industrial projectors, research lasers, medical device lasers for the surgery of eye or skin treatment (Fda.gov 2018).

Types of lasers

 In Singapore, lasers come under the legislation of the Radiation Protection Act and also within the purview of its regulations. This is also administered by the National Environmental Agency (NEA). Within the purview of this legislation, all the class 4 and the class 3b apparatus and it also includes the laser pointers which also belong to these classes are controlled apparatus. The owners of these laser devices are made mandatory to have the licenses so that a person can legally possess the device and use it as well. Any person found business possessing the laser device which belongs to the class 3b and class 4 without the proper licence that is provided by the Director-General of Environmental Protection will be considered to be guilty. The punishment for this offence can be imprisonment for up to 5 years or 100 thousand dollars fine (Nea.gov.sg 2018).

Majority of the international and the national standards focus on the safety which is based on theory and thus includes a mathematical approach. The users of the Lasers must have the technical knowledge of how to work with the lasers and it includes the laser classification, maximum permissible exposure, optical density levels, nominal ocular hazard area, exposure limits. This information is not included in the medical education programs and the and at the same time is not necessary for the healthcare professionals to perform the calculation during operation. This information is only needed to increase the awareness of the practitioners so that they become aware of the concepts and how they impact the procedure and policy (Castelluccio 2012).

If the attributes of the laser are all well understood, then such hazards can be averted. Hazard arise from the dangerous conditions, through the unanticipated exposure of the materials and tissues to the laser energy or laser light. Direct beam hazards on the explosion of the gases, drape fire, endotracheal tube fire, eye damage, tissue burns and also include hazards from the non-beam hazards. The non-beam hazards include the airborne contaminants generated through a laser (surgical plume), system failures, toxic dyes and electrical damage (Allmen and Blatter 2013).

 The risk is also identified and defined as the level of exposure that will result in injury and identifiable hazards. Levels of risk will differ depending on each person associated with the laser equipment and each member of the leaser team. The risk level may vary with the clinical application of a system and it depends on the experience of both the users and operators, training, levels of education, target tissues, power parameters, delivery device. The people that are present in a treatment room where the class 4 or class 3b laser is used in the healthcare system, there is a huge chance of risk exposure for the eyes. The level of eye damage from the laser will depend on the wavelength of the laser light. For example, a laser light of wavelength 10,600 nm is capable enough to generate heat that can cause flammability hazards. The users that are using such lasers need to be cautious of keeping the dry objects and alcohol solutions in the vicinity of the laser. Another example of the low-level laser operating at the wavelength of 780 nm and when delivered from a single handheld device does not require much safety controls. There are however hazards arising from the ocular protection (Forbes 2014).

Laser classification and safety measures

 Laser viewing cards- cards are used for viewing the cards that are not in the visible spectral range. Such laser beams fall in the regions of ultraviolet or infrared regions. It is also essential for them to have a certain way so that the profiles of the beam become visible. A low cost of viewing such as lasers in the non-visible range is through the usage of viewing cards, which are also called detector cards and infrared sensor cards. These tools are made up of plastic and are almost the size of a credit card. The viewing cards have a photosensitive area which emits the visible light when it is hit by a laser light of a particular wavelength. Some of the operation principles upon which the principles of viewing cards are based are phosphorescence, upconversion fluorescence, direct generation of fluorescence, thermochromic materials (Rp-photonics.com 2018).

Proper eyewear- usage of the proper eyewear is based on the selection of the wavelength of the laser used, radiant exposure, visible light transmission requirements, comfort, adequate prescription lenses and peripheral vision. It also involves the taking out of the reflective substances like the removal of the jewellery, watches and coins. Following the standard operating procedure when using the class 3b and class 4 lasers. Avoiding the eye level beams and blocking the beam when inserting the new optical elements (Ehs.washington.edu 2018).

 Skin protection- skin can be protected through the usage of the gloves and clothing which are based on the maximum permissible exposure. Also, a person needs to be cautious when operating with the viewing cards for the higher range optical spectrum (Ehs.washington.edu 2018).

Engineering controls- the major type of the engineering controls include the key control, remote interlock, beam enclosures, protective filter installations, attenuators and barriers (Ehs.harvard.edu 2018).

Administrative controls- the various administrative control measures include the training, instruction and information; signage; specific and through controls; laser equipment registration (arrangement for maintenance), laser user registration (arrangement for servicing and usage) (Environmental Health and Safety 2018).

Engineering controls- these are the safety feature that is inbuilt within the laser equipment supplied by the manufacturers. This laser equipment must comply with the FDA and the IEC standards. This laser equipment comes fitted with the safety features like the beam attenuators, housing interlocks, emergency off control, standby control, visible and audible emission indicators and guarded foot switch (Lawrence 2017).

Ocular hazards and the protective measures- class 4 and class 3b lasers can have the direct and indirect impact upon the eye and can be mitigated only through wearing of the protective eyewear (Yiu, Itty and Toth 2014).

Laws and regulations related to laser usage

Laser safety officer- one of the control measure is the appointment of a laser safety officer who will deal with the management of the risk. The laser safety officer also has the authority that ensures the compliance with the applicable rules and standards. The person should be competent to validate the skills and the knowledge of the personnel involved along with the assessment of all the system. The Laser safety officer can a properly qualified person, a nurse, a physician, biomedical engineer, safety consultant, practice manager, infection control officer, occupational safety and health officer or a risk manager. The laser safety officer will also be responsible for the technological assessments, and also provide his advice on the purchases of the laser equipment (Barat 2012).

 Electrical hazards (shocks)- a person can get electrical shocks due to the usage of the heavy duty industrial plugs and wires; ribbons and cables that are of flexible nature. This can be effectively mitigated by labelling the electrical equipment and the faulty equipment are labelled and removed from service (Ehs.princeton.edu 2018).

Fire hazard (fire or explosion)- usage of the fire retardants clothing and materials; usage of the valid firefighting equipment; personnel trained in the firefighting and the also in the emergency preparedness; emergency access point is kept unobstructed (Ehs.princeton.edu 2018).

 Laser Gas Air contaminates- laser plumes that contain the bacterial spores, carcinogens, fine dust mutagen, irritants, metal oxides, viruses and cancer cells. Respiratory protection; localized ventilation system through the high-efficiency particulate air (HEPA) filters and plume scavenging systems (PSS) capture and neutralizes the plume (Lsdm.ucop.edu 2018).

Tripping hazard- effective cable management is the main, always maintaining proper housekeeping all the times.

Conclusion

Form the above study it can be concluded that, laser psychology has been devised from the needs generating from the hospital operating rooms. The responsibility of the laser equipment is not just taken up by the hospital staff and the individual users and but also by the equipment manufacturers. There are risks that arise due to the insufficient knowledge of the practitioners that operate on the laser systems. The risk then leads to the potential hazards and the again lead to further health risks and organ damage. The control measures then come into play that assesses the technical and the human practise errors. This study empathises on the laser light and the various risks, hazards as well as the control measures.

References

Allmen, M.V. and Blatter, A., 2013. Laser-beam interactions with materials: physical principles and applications (Vol. 2). Springer Science & Business Media.

Barat, K.L., 2012. Laser safety in the lab. Society of Photo-Optical Instrumentation Engineers (SPIE).

Castelluccio, D., 2012. Implementing AORN recommended practices for laser safety. AORN journal, 95(5), pp.612-627.

Ehs.harvard.edu, 2018. [online] Ehs.harvard.edu. Available at: https://www.ehs.harvard.edu/node/7566 [Accessed 7 May 2018].

Ehs.princeton.edu, 2018. Section 2: Laser Hazards. [online] Ehs.princeton.edu. Available at: https://ehs.princeton.edu/book/export/html/363 [Accessed 7 May 2018].

Ehs.washington.edu, 2018. [online] Ehs.washington.edu. Available at: https://www.ehs.washington.edu/system/files/resources/lasermanual.pdf [Accessed 7 May 2018].

Environmental Health and Safety, 2018. Control Measures by Laser Classification. [online] Environmental Health and Safety. Available at: https://ehs.oregonstate.edu/laser/training/control-measures-laser-classification [Accessed 7 May 2018].

Fda.gov, 2018. Laser Products and Instruments. Retrieved from https://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/HomeBusinessandEntertainment/LaserProductsandInstruments/default.htm

Forbes, A. ed., 2014. Laser beam propagation: generation and propagation of customized light. CRC Press.

Lawrence, J.R. ed., 2017. Advances in laser materials processing: technology, research and applications. Woodhead Publishing.

Lsdm.ucop.edu, 2018. Laser Generated Air Contaminants (LGACs) | Lab Safety Design Manual. [online] Lsdm.ucop.edu. Available at: https://lsdm.ucop.edu/sections/laser-generated-air-contaminants-lgacs [Accessed 7 May 2018].

Menzel, R., 2013. Photonics: linear and nonlinear interactions of laser light and matter. Springer Science & Business Media.

Meschede, D., 2017. Optics, light and lasers: the practical approach to modern aspects of photonics and laser physics. John Wiley & Sons.

Nazemisalman, B., Farsadeghi, M. and Sokhansanj, M., 2015. Types of lasers and their applications in pediatric dentistry. Journal of lasers in medical sciences, 6(3), p.96.

Nea.gov.sg. (2018). Lasers and Laser Pointers. Retrieved from https://www.nea.gov.sg/anti-pollution-radiation-protection/radiation-protection/lasers-and-laser-pointers

Rp-photonics.com, 2018. Encyclopedia of Laser Physics and Technology - laser viewing cards, infrared sensor cards, detector cards, sensitivity, mid-IR, phosphorescence, fluorescence, upconversion, thermochromic. Retrieved from https://www.rp-photonics.com/laser_viewing_cards.html

Warwick.ac.uk, 2018. Laser Classification. [online] Warwick.ac.uk. Available at: https://warwick.ac.uk/services/healthsafetywellbeing/guidance/lasers/appendix1classification/ [Accessed 7 May 2018].

Yiu, G., Itty, S. and Toth, C.A., 2014. Ocular safety of recreational lasers. JAMA ophthalmology, 132(3), pp.245-246.