Revenue Recognition Disaggregation of revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 01, 2022	Jan. 02, 2021
Disaggregation of Revenue [Line Items]
Net sales	$ 384,507	$ 326,053
OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	242,970	211,162
Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	141,537	114,891
Products | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	148,525	125,577
Products | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	115,641	89,312
Other products and services revenues | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	94,445	85,585
Other products and services revenues | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	25,896	25,579
Sales of spare parts
Disaggregation of Revenue [Line Items]
Net sales	17,500	16,000
Microelectronics | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	149,003	128,173
Microelectronics | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	24,019	20,675
Precision manufacturing | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	14,441	11,859
Precision manufacturing | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	90,113	69,591
Instrumentation | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	75,013	67,276
Instrumentation | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	18,930	17,951
Aerospace and defense | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	4,513	3,854
Aerospace and defense | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	$ 8,475	$ 6,674