Problem; Problem. 2. There is a broad range of materials that can be cut with a laser: wood, plastic, cardboard, textile... Laser cutting works by directing the output of a high-power laser through optics. << Suppose when two photons each of amplitude are in phase with other, then young’s principle of superposition, the resultant amplitude of two photons is 2 and the intensity is 4 . 2. are the pump frequency and the laser frequency respectively. and This is because of coherence and directionality of laser. 1. What is the radius of the beam at the waist (considering the waist and the laser are in the same plane)? Determine the value of the gain needed in the amplifying medium to obtain laser oscillation. Solution. Typically, lasers are thought of as emitting li… I have to say that after reading all kinds of flower problems and solutions, I feel a lot of knowledge. endobj xڝ�wTT��Ͻwz��0�z�.0��. stream Calculate the gap in frequency between two longitudinal modes in a linear cavity whose optic length, L, =300 mm. g� �����oc�n/�~ X�'a�ؠ���ӗ������S%%r^{) 9=r9�6D�O�.9�O��b_'>o�8��N]ݯ����ܔ�� ��ٞ���9oUW��^� ������,(X0*������`���t7f�7��[
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�ȉ��9. An one milliwatt He-Ne laser is highly intense than the sun intensity. There are no other energy levels nearby. >> ��OU�S1z6��wM�,��7���](�i�yJӲ�i�w6�+�*���&��羸�+-B[��Y�`���1ΗrF��6?�%А�@L��ra�3� |��� La�]��yW�����bX���`���3� By considering the energy of the ground state to be zero and calling 0 the ground state and 1 the lower energy level: Thus 38% of the population is in the lower energy level. A helium-neon laser emitting at 633 nm makes a spot with a radius equal to 100 mm at 1/e2 at a distance of 500 m from the laser. x��Z͎�6��)��J�~�� Calculate the energy of each pulse. ����rh�c��6��Ĩo�jl�4��n����;�]`��!��bH�g�ȳD�t��zo���KP�c�r2��y��i5�7�ނBV4��Lko)Q����H��җ����ܳ#8Jv�B=�kv�]�q ~�iH�����}P?�م��.M 峩�b�Q,�J��[email protected] when laser oscillation occurs. %PDF-1.5 Solution of Problem 4.12 Problem 4.13 A laser emitting at 0=850nm has a gain spectral width of = 32 nm and a peak gain of g(0) 50/cm , Plot g() equation 4.41. /Filter/FlateDecode endstream TYPES OF LASERS 301 570-640 nm (rhodamine 6G) and many others. By taking into account the different wavelengths, the power is equal to. . These dyes can be excited by optically with Argon lasers for example and emit at 390-435nm (stilbene), 460-515nm (coumarin 102), 7.3. ��� k��p�N����+�.��sKq������qV�CX|�m��Y�8���fɞ��^=�s�E\� The term "laser" is an acronym for Light Amplification by Stimulated Emission of Radiation. �jN�jWma��]-`ȏl�D?��[email protected];��&�%�/}vIh�\��ņv�CD�N����湣-�|u_��2��u\d��i��7� �N�� Thus, the gap separating the end of the spectral band from the closest longitudinal mode is equal to: The frequency of a mode can be expressed by: E�����z6��Cf.�+So�f���(�Q�g�)��L�7���F��c��?��3�*P�#wR���x��`�_����P�䮤��C�lJ���O��`�����)�@�_�'*�:�%&z���3X]P�߀S��a�8 Calculate the number of longitudinal modes that can oscillate in this cavity. If an external electric ﬁeld is applied to a dielectric (not conduct- ing) material the material will be polarized, resulting in a polarization P. The relation is then, E = D "0 P "0) D = "0E +P If P = 0, as in vacuum, E and D are in phase. >> A ring laser cavity is composed of 4 identical mirrors with a reflection coefficient equal to 0.99. 2. $E}k���yh�y�Rm��333��������:�
}�=#�v����ʉe The linear cavity is 30 cm long. At what distance must the cavity mirror be placed so that at least one of the modes falls in the amplification band? Consider a lower energy level situated 200 cm-1 from the ground state. For simplicity, the spectral profile is assumed to be rectangular. )ɩL^6 �g�,qm�"[�Z[Z��~Q����7%��"� What is the rate of repetition of the pulses emitted by a mode-locked laser? >> In a ring lasercavity, the beam passes through the medium only once each turn. It is also widely used in industrial production and processing. 69 0 obj , where endobj $O./� �'�z8�W�Gб� x�� 0Y驾A��@$/7z�� ���H��e��O���OҬT� �_��lN:K��"N����3"��$�F��/JP�rb�[䥟}�Q��d[��S��l1��x{��#b�G�\N��o�X3I���[ql2�� �$�8�x����t�r p��/8�p��C���f�q��.K�njm͠{r2�8��?�����.