Abstract: An inner focus lens system, in order from an object side, comprising: a first lens unit including a most-object-side negative first lens element; a positive second lens unit; and a negative third lens unit, wherein an aperture diaphragm is included, the first lens unit, the third lens unit, and the aperture diaphragm are fixed relative to an image surface in focusing, the second lens unit moves relative to the image surface in the focusing, and the conditions: BF/Y<1.7 and TH/f>1.6 (BF: a distance from an apex of an image-side surface of a most-image-side lens element to the image surface, Y: a maximum image height, TH: a distance from an apex of an object-side surface of a most-object-side lens element to the apex of the image-side surface of the most-image-side lens element, f: a focal length of the lens system) are satisfied.

Abstract: An inner focus lens system comprising lens units each composed of at least one lens element, wherein a most object side lens unit is provided and is fixed with respect to an image surface in focusing, and the conditions: BF/Y<1.7 and (L×FNo)/f<2.2 (BF: a distance from an image side surface apex of a most image side lens element to the image surface, Y=f×tan ?, L: an overall length of lens system, FNo: a F-number of lens system, f: a focal length of lens system, ?: a half view angle of lens system) are simultaneously satisfied, or only the condition: (L×FNo)/f<2.0 (L: the overall length of lens system, FNo: the F-number of lens system, f: the focal length of lens system) is satisfied.

Abstract: There are provided an inner focus lens consisting of a first lens group, an aperture diaphragm, and a second lens group in order from an object side. The first lens group has a positive first lens element, a positive second lens element, and a negative third lens element; or a positive first lens element, a positive second lens element, a positive third lens element, and a negative fourth lens element, in order from the object side. One lens element in the second lens group is moved with respect to an image surface in focusing, some of the lens elements thereof are moved in a direction perpendicular to an optical axis. The inner focus lens satisfies 0.2<|fF/fO|<3.0 (fF: a focal distance of a focus lens, fO: a synthetic focal distance of the lens elements moving in the direction perpendicular to the optical axis).

Abstract: There are provided an inner focus lens consisting of a first lens group, an aperture diaphragm, and a second lens group in order from an object side. The first lens group has a positive first lens element, a positive second lens element, and a negative third lens element, or has a positive first lens element, a positive second lens element, a positive third lens element, and a negative fourth lens element, in order from the object side. One lens element in the second lens group is moved with respect to an image surface in focusing. The second lens group has five or more lens elements, and has a configuration including a negative lens element, a positive lens element, and a positive lens element in order from the object side.

Abstract: An inner focus lens system comprising a first lens unit and subsequent lens units, wherein the first lens unit: is fixed with respect to an image surface in focusing; and includes a first positive lens element located closest to the object side and a second positive lens element, the subsequent lens units include only a first focusing lens unit located closest to the object side and a second focusing lens unit, at least one of the first focusing lens unit and the second focusing lens unit is composed of two or less lens elements, and the subsequent lens units include an image blur compensating lens unit.

Abstract: An inner focus lens system comprising a first lens unit and subsequent lens units, wherein an aperture diaphragm is provided, the first lens unit is: fixed with respect to an image surface in focusing; and composed of five or more lens elements including a first positive lens element located closest to the object side and a second positive lens element, the subsequent lens units include at least a first focusing lens unit located closest to the object side and a second focusing lens unit, at least one of the first focusing lens unit and the second focusing lens unit is composed of two or less lens elements, at least one lens element is provided on the image side relative to the aperture diaphragm, and the condition: NF1?NF2 (NF1, NF2: the number of lens elements constituting the first, second focusing lens unit) is satisfied.

Abstract: A terahertz light generation device 1 comprises a resonator structure 12 for intensifying incident light and outputting the intensified light and laser oscillation units 10, 11 for feeding the incident light into the resonator structure 12. The incident light comprises first and second incident light components having polarization states different from each other and frequencies different from each other. The laser oscillation units 10, 11 feed the resonator structure 12 with the first and second incident light components at an angle inclined from a principal surface in the resonator structure 12. The resonator structure 12 outputs light having a frequency corresponding to the difference between the respective frequencies of the first and second incident light components.

Abstract: There are provided an inner focus lens consisting of a first lens group, an aperture diaphragm, and a second lens group in order from an object side. The first lens group has a positive first lens element, a positive second lens element, and a negative third lens element, or has a positive first lens element, a positive second lens element, a positive third lens element, and a negative fourth lens element, in order from the object side. One lens element in the second lens group is moved with respect to an image surface in focusing. The second lens group has five or more lens elements, and has a configuration including a negative lens element, a positive lens element, and a positive lens element in order from the object side.

Abstract: There are provided an inner focus lens consisting of a first lens group, an aperture diaphragm, and a second lens group in order from an object side. The first lens group has a positive first lens element, a positive second lens element, and a negative third lens element; or a positive first lens element, a positive second lens element, a positive third lens element, and a negative fourth lens element, in order from the object side. One lens element in the second lens group is moved with respect to an image surface in focusing, some of the lens elements thereof are moved in a direction perpendicular to an optical axis. The inner focus lens satisfies 0.2<|fF/fO|<3.0 (fF: a focal distance of a focus lens, fO: a synthetic focal distance of the lens elements moving in the direction perpendicular to the optical axis).

Abstract: A zoom lens system, in order from an object side to an image side, comprising: a first lens unit having negative optical power; a second lens unit having positive optical power; a third lens unit having negative optical power; and a fourth lens unit having positive optical power, wherein the third lens unit is composed of two or less lens elements, the fourth lens unit is composed of two or less lens elements, the first lens unit has at least one air space between lens elements constituting the first lens unit, and the condition: Dair/fW>0.75 (Dair: an air space located on the most object side in the first lens unit, fW: a focal length of the entire system at a wide-angle limit) is satisfied; an imaging device; and a camera are provided.

Abstract: A zoom lens system comprising: a negative first lens unit; a positive second lens unit; and a positive third lens unit, wherein the first to third lens units are individually moved along an optical axis to vary magnification in zooming, the first lens unit is composed of two lens elements and includes a positive lens element having at least one aspheric surface, the third lens unit is composed of one lens element, and the condition: 1.74<Ir/?(|DL1×fG1|) (DL1: an optical axial thickness of an object side first lens element in the first lens unit, fG1: a focal length of the first lens unit, Ir=fT×tan(?T), fT and ?T: a focal length of the entire system and a half value of maximum view angle at a telephoto limit) is satisfied; an imaging device; and a camera are provided.

Abstract: A zoom lens system comprising: a first lens unit having negative optical power; a second lens unit having positive optical power; and a third lens unit having positive optical power, wherein the first to third lens units are individually moved along an optical axis to vary magnification in zooming, each lens unit includes at least one lens element that satisfies the conditions: nd?1.67, vd<59 and 0.000<PgF+0.002×vd?0.664 (nd, vd and PgF: a refractive index to the d-line, an Abbe number to the d-line and a partial dispersion ratio, of the lens element), and the condition: 0.31<Ir/?(|fG1×fG2|) (Ir=fT×tan (?T), fT and ?T: a focal length of the entire system and a half value of maximum view angle, at a telephoto limit, fG1 and fG2: a focal length of each of the first lens unit and the second lens unit) is satisfied; an imaging device; and a camera are provided.

Abstract: A composite photonic structure element comprises a photonic crystal and multilayer films. The photonic crystal is formed by alternately laminating a plurality of sets of an active layer having a nonlinear effect for converting a fundamental wave into a second harmonic and an inactive layer having no nonlinear effect, and is constructed such that the energy of the fundamental wave coincides with a photonic bandgap end. Each of the multilayer films is formed by laminating a plurality of sets of two kinds of thin films having different refractive indexes and reflects the fundamental wave. The multilayer films are connected to both ends of the photonic crystal. The fundamental wave enters one of end faces and is reciprocally reflected between resonators having the multilayer films, so that the intensity of the fundamental wave is enhanced within the photonic crystal. The fundamental wave is converted into a second harmonic in the active layer, and the second harmonic is taken out from the other end face.