Lasers Essay Example | Topics and Well Written Essays - 1500 words - 1

Lasers - Essay Example 13). â€Å"The invention of the laser was one of the groundbreaking scientific achievements of the twentieth century† (Lang and Barbero vii). This technology resulted in the development of new systems of communication, optical devices, space exploration, digital devices, and the mastery of nuclear energy. Lasers are oscillators functioning at optical frequencies producing monochromatic, coherent, and highly collimated intense beams of light. The frequencies of operation lie within a spectrum of far infrared to the vacuum ultraviolet or soft X-ray region (Lang and Barbero xii). This process occurs â€Å"when a beam of light passes through a specially prepared medium and intiates or stimulates the atoms within that medium to emit light† (Silfvast 1). Light is emitted from a source such as a flash lamp or diode, and the light is amplified in the lasing media which may be a gas, liquid, or solid. â€Å"The light travels between two mirrors; one of the mirrors is 100% reflective, while the other is partially translucent† (Dajnowski et al. 13). Light repeatedly passes through the lasing media until it gains the required energy level, at which point it exits through the partially reflective, translucent mirror, state Dajnowski et al. (13). The light is released in exactly the same direction and same wavelength as that of the original beam. Thus, lasers are devices that â€Å"amplify or increase the intensity of light to produce a highly directional, high-intensity beam that typically has a very pure frequency or wavelength† (Silfvast 1). The components of a typical laser device include an amplifying or gain medium, a pumping source to channel energy into the device, and an optical cavity or mirror arrangement for reflecting the beam of light back and forth through the amplifying medium for further increase and intensification. â€Å"A useful laser beam is obtained by allowing a small portion of the light to escape by passing through one of the mirrors that is

The effect of immigration on US economy Essay Example | Topics and Well Written Essays - 1250 words

The effect of immigration on US economy - Essay Example This decrease was a result of reduced job opportunities and increased law enforcement. (Giovanni 24) Despite this reduction, researchers found that the reproduction could have contributed the reduction of immigrants. A good number of immigrants have children, who are recognized legally as US citizens, others intermarried gaining their citizenship by marriage. Although it is hard to estimate the actual number of immigrants living in the US, researchers estimated that a third of the total population living in the US is illegal. Recent reports released by the center for immigration studies showed that in the year 2012, 12 million immigrants arrived in the United States temporally using non-immigrants visas. This figure translates to a 50% total population by the year 2000. Significant number of these illegal immigrants was from Mexico. For over a decade, there has been rapid distribution of immigrants in the United States. Georgia reported the immigrant population growth rate of 152% between year 2000 and 2007. California grew by 10.2%, registering the largest number of immigrants in the United States. Consequently, California can comfortably offset its fiscal cost. Although this immigration may be caused by historical and geographical factors, economic growth is achieved. For instance, if a state is experiencing rapid growth in terms of economic conditions, it might end up encouraging immigrants and affect income, output and employment. Analysis by various physiologists says that, reasonable arguments are being raised to protect all American-born workers from competition from immigrants. The United States government is enforcing strict laws to prioritize recognition of American born citizen (Nwosu, Batalova and Auclair 56). Immigrants are allowed to keep transportation, natural resources, construction and maintenance occupation and material moving occupations. On the other hand, the