laser pulses - 2025 ACF Regionals

Question

In one process, the time between these phenomena is bounded by an expression whose numerator contains the time–bandwidth product of a distribution, which for Gaussian profiles is 0.441. For 10 points each:

[10h] Name these phenomena that were generated in a Kerr cell by Hellwarth and McClung in 1961 through a process that periodically adjusts the Q-factor of a resonator.

ANSWER: laser pulses [accept pulsed lasers; prompt on lasers; prompt on laser peaks or laser intensity peaks by asking “what causes those?”]

[10m] Pulse generation can occur through a process that is said to “lock” either these patterns or phase. Coupled systems produce the “normal” form of these patterns at resonant frequencies.

ANSWER: modes [accept normal modes or mode-locking]

[10e] Another method for pulse generation is gain-switching, where the gain of a laser is the change in this quantity. In electronic amplifiers, gain is usually quantified as a ratio of this quantity measured in watts.

ANSWER: power [accept optical power]

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Summary


Florida	2025-02-01	Y	3	13.33	100%	33%	0%
Great Lakes	2025-02-01	Y	6	13.33	100%	33%	0%
Lower Mid-Atlantic	2025-02-01	Y	6	11.67	100%	17%	0%
Midwest	2025-02-01	Y	6	21.67	100%	100%	17%
North	2025-02-01	Y	3	13.33	100%	33%	0%
Northeast	2025-02-01	Y	5	14.00	100%	40%	0%
Overflow	2025-02-01	Y	4	15.00	100%	50%	0%
Pacific Northwest	2025-02-01	Y	2	15.00	100%	50%	0%
South Central	2025-02-01	Y	2	15.00	100%	50%	0%
Southeast	2025-02-01	Y	4	15.00	100%	50%	0%
Upper Mid-Atlantic	2025-02-01	Y	9	13.33	89%	44%	0%
Upstate NY	2025-02-01	Y	3	13.33	100%	33%	0%

Data


Illinois B	Chicago B	0	10	10	20
Chicago C	Illinois A	0	10	10	20
Chicago A	Chicago D	10	10	10	30
Missouri	Illinois C	0	10	10	20
WashU A	Indiana B	0	10	10	20
Cornell C	Binghamton A	0	0	10	10
RIT A	Cornell D	0	10	10	20
Michigan A	Carnegie Mellon A	0	0	10	10
Michigan C	Carnegie Mellon B	0	0	10	10
Kenyon	Case Western B	0	0	10	10
Ohio State B	Michigan D	0	10	10	20
Michigan B	Michigan State	0	0	10	10
Ohio State A	Case Western A	0	10	10	20
Duke	Liberty A	0	0	10	10
South Carolina	Liberty B	0	0	10	10
UNC B	William & Mary	0	10	10	20
UNC C	Virginia Tech A	0	0	10	10
UNC D	Virginia A	0	0	10	10
Wake Forest	Liberty C	0	0	10	10
Georgetown A	Northwestern B	0	0	10	10
Notre Dame B	Notre Dame C	0	0	10	10
Purdue	Iowa	0	10	10	20
Northwestern A	Stanford B	0	10	10	20
UW B	Alberta	0	0	10	10
UBC	UW A	0	10	10	20
ASU	Texas B	0	0	10	10
Texas A	TAMU	0	10	10	20
Florida A	Valencia A	0	0	10	10
Florida State A	UCF B	0	0	10	10
Florida B	UCF C	0	10	10	20
Indiana A	WashU B	0	10	10	20
Iowa State	Carleton	0	10	10	20
Minnesota B	Winona State	0	0	10	10
Wisconsin A	Wisconsin B	0	0	10	10
Brandeis A	BU	0	0	10	10
Harvard A	Brandeis B	0	0	10	10
Dartmouth A	Harvard B	0	0	10	10
Brown A	Tufts A	0	10	10	20
MIT A	UMass Boston	0	10	10	20
Tennessee A	Georgia Tech A	0	0	10	10
Louisville A	Georgia Tech C	0	0	10	10
Georgia Tech B	Vanderbilt A	0	10	10	20
Bruin A	Alabama A	0	10	10	20
Cornell B	NYU A	0	0	10	10
George Washington A	Haverford B	0	0	10	10
Columbia C	John Jay College	0	0	10	10
Johns Hopkins A	Maryland A	0	10	10	20
George Washington B	NYU B	0	0	0	0
Haverford A	Penn B	0	10	10	20
Penn A	Rutgers A	0	10	10	20
Maryland B	Vassar A	0	0	10	10
Columbia B	Yale A	0	10	10	20
RIT B	ESF A	0	0	10	10