Thermal-mechanical adjustment for laser system

TECHNICAL FIELD

0001The present invention relates generally to a laser system. In particular, the present invention relates a laser system having a thermal-mechanical adjustment device.

BACKGROUND

0002Semiconductor lasers are used in many different applications. These applications can include monitoring systems and measurement systems. In a monitoring system for high-powered machinery such as a power transformer, a laser e.g., a quantum cascade laser (QCL) is used for detecting trace gases. Selection of the wavelength of the light emitted is determined by the temperature of the laser medium. Therefore, the laser assembly needs to be kept at a specific temperature to maintain accuracy of the wavelength thereof.

0003<patcit id="pcit0001" dnum="US2003231690A"><text>US 2003/231690</text></patcit> describes a method for optimizing feedback suppression of optical isolators when used with variable wavelength light sources. The method comprises positioning an optical isolator in a light beam, and adjusting feedback suppression by the optical isolator according to wavelength of the light beam. Adjusting the feedback suppression may comprise adjusting temperature of the optical isolator or a non-reciprocal rotator associated with the isolator.

0004<patcit id="pcit0002" dnum="US2005123008A"><text>US 2005/123008</text></patcit> describes a control technique and apparatus for an external cavity diode laser (ECDL). Coarse tuning adjustments for the ECDL are performed by varying the temperature of tunable filters and fine tuning adjustments may be performed varying the temperature of the ECDL base to vary the length of the cavity via thermal contraction and expansion. A controller comprises a coupler matrix that mathematically relates multiple control signal inputs for varying the temperatures of the tunable filters and base to produce multiple outputs used to control, for example, thermal-electric cooler (TEC) elements associated with the tunable filters and base.

0005Us 6822996 describes a laser apparatus comprising a rigid unitary mount base, a gain medium rigidly mounted with respect to the mount base in a position defining a first end of an external cavity, the gain medium having first and second output facets, a reflector rigidity mounted with respect to the mount base in a position defining a second end of the cavity, a tuning element rigidly mounted with respect to the mount base in the external cavity between the gain medium and the reflector, a collimator rigidly mounted with respect to the mount base, between a first facet of the gain medium and the tuning element and an optical output assembly rigidly mounted to the mount base and optically coupled to a second facet of the gain medium.

0006Current laser systems can employ a combination of fans and heat pipes to remove excess heat generated from the laser beam. However, fans can create undesired noise and vibrations, which increases the noise within the laser system.

SUMMARY OF THE EMBODIMENTS

0007Embodiments of the present invention provide a laser system including a thermal-mechanical adjustment device capable of maintaining alignment of the laser beam and dissipating heat therefrom to maintain accuracy of the wavelength of the light output.

0008The invention resides in a laser system as defined in the appended claims.

0009The foregoing has broadly outlined some of the aspects and features of various embodiments, which should be construed to be merely illustrative of various potential applications of the disclosure. Other beneficial results can be obtained by applying the disclosed information in a different manner or by combining various aspects of the disclosed embodiments. Accordingly, other aspects and a more comprehensive understanding may be obtained by referring to the detailed description of the exemplary embodiments taken in conjunction with the accompanying drawings, in addition to the scope defined by the claims.

DESCRIPTION OF THE DRAWINGS

0010<ul id="ul0001" list-style="none"><li><figref idref="f0001">FIG. 1</figref> is a schematic illustrating an example of a laser system that can be implemented within one or more embodiments of the present invention.</li><li><figref idref="f0002">FIG. 2</figref> is a detailed schematic of a thermal-mechanical adjustment device of the laser system of <figref idref="f0001">FIG. 1</figref> that can be implemented within one or more embodiments.</li><li><figref idref="f0003">FIG. 3</figref> is a schematic illustrating a mechanical adjustment operation of the thermal-mechanical adjustment device of <figref idref="f0002">FIG. 2</figref> that can be implemented within one or more embodiments of the present invention.</li><li><figref idref="f0004">FIG. 4A</figref> and <figref idref="f0005">4B</figref> are schematics illustrating a heat dissipation operation of the thermal-mechanical adjustment device of <figref idref="f0002">FIG. 2</figref> that can be implemented within one or more embodiments of the present invention.</li></ul>

0011The drawings are only for purposes of illustrating preferred embodiments and are not to be construed as limiting the disclosure. Given the following enabling description of the drawings, the novel aspects of the present disclosure should become evident to a person of ordinary skill in the art. This detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of embodiments of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

0012As required, detailed embodiments are disclosed herein. It must be understood that the disclosed embodiments are merely exemplary of various and alternative forms. As used herein, the word "exemplary" is used expansively to refer to embodiments that serve as illustrations, specimens, models, or patterns. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. In other instances, well-known components, systems, materials, or methods that are known to those having ordinary skill in the art have not been described in detail in order to avoid obscuring the present disclosure. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art.

0013Embodiments of the present invention provide a laser system housing a laser holder for transmitting a laser beam therethrough, and a thermal-mechanical adjustment device capable of adjusting the temperature of the laser beam and maintaining the alignment of the laser beam. The thermal-mechanical adjustment device effectively maintains accuracy of the wavelength of the light output.

0014Details regarding the laser system 100 of the present invention will now be discussed with reference to <figref idref="f0001 f0002 f0003">FIGS. 1 through 3</figref>. <figref idref="f0001">FIG. 1</figref> illustrates a laser system 100 used to perform various testing operations on target equipment 50 e.g., such as a power transformer. For example, the testing operations can include trace gases detection. The laser system 100 can be a semiconductor laser such as a quantum cascade laser (QCL). Other types of lasers could also be used with this laser system 100, for example telecommunication lasers, lead salt lasers, vertical cavity surface emitting laser (VCSEL), Hybrid silicon laser, InGaAsp laser, semiconductor laser diode, doped insulator lasers, or gas and chemical lasers, etc.

0015As further shown in <figref idref="f0001">FIG. 1</figref>, the laser system 100 includes a laser holder 110 for transmitting a laser beam 120 therethrough emitting from a laser source. One or more lens 125 are disposed downstream of the laser holder 110 for reflecting the laser beam 120 in a desired direction. In <figref idref="f0002">Fig. 2</figref>, the laser system 100 further includes a laser head (i.e., a mounting stand) 130 adjacent to the laser holder 110 holding the laser beam 120 and lens 125. The laser head 130 includes a chamfered opening 132, and a thermal-mechanical adjustment device 140 including a pivot bar 141 for maintaining the alignment of the laser beam 120. The laser head 130 can be formed of a metal material such as copper or any other suitable material.

0016Further in <figref idref="f0002">FIG. 2</figref>, the chamfered opening 132 of the laser head 130 is formed at one end of the laser head 130 opposite the emitting end of the laser beam 120 from the laser source, and is configured to house the pivot bar 141 therein. The pivot bar 141 is configured to allow pivot in conjunction with the chamfered opening and rotation of the laser beam 120 about its circumference at a pivot point (as depicted by dashed line 'A' in <figref idref="f0003">FIG. 3</figref>). The chamfered opening 132 is configured to allow the pivot bar 141 to sway at an angle of approximately 90° to the rotation of the pivot bar 141 (as depicted by dashed line 'B' in <figref idref="f0003">FIG. 3</figref>). Thus, the pivot bar 141 allows x and y axis alignment of the laser beam 120. When only 1-axis alignment is needed, the rotation around the pivot bar. Alternatively, when 2-axis alignment is needed, then both rotation and pivoting operations are performed.

0017The thermal-mechanical adjustment device 140 of the laser system 100 further includes a plurality of first thermally conductive portions 142a and 142b disposed at opposite sides of the laser head 130 adjacent to respective ends of the pivot bar 141. According to one or more embodiments, the thermally conductive portions 142a and 142b can be formed of thermally conductive foam or any other suitable material for the purposes set forth herein.

0018A spring device 143 is also provided and is disposed at along the laser head 130 at another end of the laser head 130 opposite the end housing the pivot bar 141. Additionally, according to one or more embodiments, second thermally conductive portions 144a and 144b are disposed adjacent to the spring device 143. The second thermally conductive portions 144a and 144b can be formed of the same or different materials than that of the first thermally conductive portions 142a and 142b. The thermally conductive foam of the thermally conductive portions 142a, 142b, 144a and 144b provides a resistive force and has elastic restorative properties as well as being thermally conductive. Thus, the material could be used in conjunction with screws to allow precise alignment.

0019As shown in <figref idref="f0002">FIG. 2</figref>, the first thermally conductive portions 142a and 142b are L-shaped and the second thermally conductive portions 144a and 144b are rectangular-shaped. The present invention is not limited to the thermally conductive portions 142a, 142b, 144a and 144b being any particular shape or size, and may vary accordingly. Details regarding the operations of the first and second thermally conductive portions 142a, 142b, 144a and 144b and the spring device 143 will be discussed now with reference to <figref idref="f0003 f0004 f0005">FIGS. 3 through 4B</figref>.

0020<figref idref="f0003">FIG. 3</figref> is a schematic illustrating a mechanical adjustment operation to be performed by the thermal-mechanical adjustment device 140 according to one or more embodiments of the present invention.

0021As shown in <figref idref="f0003">FIG. 3</figref>, as indicated by the arrows, the first and second thermally conductive portions 142a, 142b, 144a and 144b are configured to apply a resistive (i.e., pushing) force to the laser head 130, while the spring device 143 is configured to apply a pulling force to the laser head 130, to assist with adjustment of the laser beam 120 being transmitted therethrough.

0022When the laser beam 120 is transmitted through the laser head 130, the first and second thermally conductive portions 142a, 142b, 144a and 144b along with the spring device 143 maintain the alignment of the laser beam, thereby maintaining the accuracy of the wavelength. The first and second thermally conductive portions 142a, 142b, 144a and 144b also dissipate heat from the laser system 100.

0023<figref idref="f0004">FIG. 4A</figref> and <figref idref="f0005">4B</figref> are schematics illustrating a heat dissipation operation of the thermal-mechanical adjustment device 140 that can be implemented within one or more embodiments of the present invention.

0024As shown in <figref idref="f0004">FIG. 4A</figref>, as indicated by the arrows, the first and second thermally conductive portions 142a, 142b, 144a and 144b are further configured to transfer heat generated by the laser beam 120 away from the laser head 130. Thus, the first and second thermally conductive portions 142a, 142b, 144a and 144b assist with maintaining the temperature of the laser beam 120 to a specific temperature range of approximately 20 to 40 degrees Celsius.

0025In some embodiments, the laser system 100 can be mounted to a mounting base 160 as shown in <figref idref="f0005">FIG. 4B</figref>. In this embodiment, the laser head 130 is secured to mounting base 160 via one or more set screws 161a, 161b and 161c. The first and second thermally conductive portions 144a and 144b are further configured to apply a pushing force against the force of the set screws 161a, 161b and 161c to maintain accuracy of the alignment of the laser beam 120.

0026Further, the heat transferred away from the laser head 130 via the first and second thermally conductive portions 142a, 142b, 144a and 144b is further transferred to the mounting base 160 to be dissipated therefrom (as indicated by the arrows). The heat can be disposed of via a heat pipe, heat sink or other heat dissipating mechanism attached to the mounting base 160. The laser system 100 of the present invention therefore effectively maintains the temperature of the laser beam 120.

0027Embodiments of the present invention provides the advantages of dissipating heat and mechanically aligning the laser beam of the laser system using the same components (i.e., the thermally conductive portions) employed therein. Further, the present invention provides a laser system without use of a fan to thereby avoid unwanted noise and vibrations in the laser system.

0028This written description uses examples to disclose the invention including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods.