26 Chap. 1 Introduction to Lasers EXERCISES Basics 1.1 (a) Describe briefly the difference between a penlight laser and a penlight flashlight. (b) Propose a simple test to differentiate a peniight laser from a penlight flashlight. 1.2 The United Federation of Planets starship Voyager is armed with phasors and photon torpedoes. Explain (citing fundamental physical principles as appropriate) why neither phasors nor photon torpedoes are advanced versions of lasers. (For those who are not Trekkies, phasors and photon torpedoes are fictional weapons from Star Trek. A phasor can be set to "stun" or "kill": an individual shot by a phasor on "stun" falls over in a faint; on "kill" the person is vaporized. Phasors usually appear orange on the TV screen and can be seen to visually travel from the source to target. Photon torpedoes are round objects shot from the starship. They impact on the target and it explodes. They also can be seen to visually travel from the source to target.) 1.3 Construct a logarithmic waveiength-frequency scale for electromagnetic radiation. Mark both frequency and wavelength on the x-axis of the scale in appropriate units (nm, um, cm. m, etc.) and (Hz. kHz. GHz, etc.). On the scale indicate the following regions: a. visible light (include red, yellow and blue), b. AM radio, c. FM radio, d. x-rays. e. gamma rays. f. S- and X-band traffic radar. and g. TV. 1.4 Complete the following table for various types of electromagnetic radiation. Center wavelength, A Center frequency, v Red light 650 nm Green light 571 THz Blue light 450 nm Yellow light 517 THz AM radio 560.3 m-186.8 m FM radio 88 MHz-108 MHz 0.1-100 A X-rays > 3.1019 Hz Gamma rays 800 nm-5 um Near infrared 2 GHz-4 GHz S-band radar TV channels 7-13 1.72 m-1.38 m Transitions between laser states 15 There are a number of ways of specifying the separation between two laser states. These include the energy difference E2 - E, in joules or eV, the wavelength A (in angstroms, nm or microns),

26 Chap. 1 Introduction to Lasers EXERCISES Basics 1.1 (a) Describe briefly the difference between a penlight laser and a penlight flashlight. (b) Propose a simple test to differentiate a peniight laser from a penlight flashlight. 1.2 The United Federation of Planets starship Voyager is armed with phasors and photon torpedoes. Explain (citing fundamental physical principles as appropriate) why neither phasors nor photon torpedoes are advanced versions of lasers. (For those who are not Trekkies, phasors and photon torpedoes are fictional weapons from Star Trek. A phasor can be set to "stun" or "kill": an individual shot by a phasor on "stun" falls over in a faint; on "kill" the person is vaporized. Phasors usually appear orange on the TV screen and can be seen to visually travel from the source to target. Photon torpedoes are round objects shot from the starship. They impact on the target and it explodes. They also can be seen to visually travel from the source to target.) 1.3 Construct a logarithmic waveiength-frequency scale for electromagnetic radiation. Mark both frequency and wavelength on the x-axis of the scale in appropriate units (nm, um, cm. m, etc.) and (Hz. kHz. GHz, etc.). On the scale indicate the following regions: a. visible light (include red, yellow and blue), b. AM radio, c. FM radio, d. x-rays. e. gamma rays. f. S- and X-band traffic radar. and g. TV. 1.4 Complete the following table for various types of electromagnetic radiation. Center wavelength, A Center frequency, v Red light 650 nm Green light 571 THz Blue light 450 nm Yellow light 517 THz AM radio 560.3 m-186.8 m FM radio 88 MHz-108 MHz 0.1-100 A X-rays > 3.1019 Hz Gamma rays 800 nm-5 um Near infrared 2 GHz-4 GHz S-band radar TV channels 7-13 1.72 m-1.38 m Transitions between laser states 15 There are a number of ways of specifying the separation between two laser states. These include the energy difference E2 - E, in joules or eV, the wavelength A (in angstroms, nm or microns),