Abstract: To alleviate the prominent yield and quality bottlenecks of cucumber (Cucumis sativus L.) under protected cultivation and explore low cost and energy saving light regulation technologies suitable for greenhouse vegetable production, spring and autumn cropping experiments were conducted from March to November 2025 in Xindu Base of Sichuan Academy of Agricultural Sciences, with the cucumber cultivar ‘Qingbai Zao’ selected as experimental material. A two factor completely randomized block experimental design with three biological replicates was adopted in this study. The two experimental factors included supplemental laser irradiation and graphene oxide (GO) root drenching. The laser factor contained two levels: laser supplementation (13 W red blue laser lamps, operated daily from 08:00 to 18:00 after seven days of field transplanting) and no laser supplementation. The GO factor involved four root irrigation concentration levels of 0, 0.25, 0.50 and 1.00 mg/L, generating eight combined treatments for each growing season. The LI 6800 portable photosynthesis system was employed to measure leaf gas exchange parameters including net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration and transpiration rate on fully expanded functional leaves at the flowering and fruit setting stages. Yield related indicators such as fruit number per plant, single fruit weight and yield per 667 m² were recorded upon commercial fruit maturity. Fruit quality indices covering soluble sugar and vitamin C contents were assayed via conventional physicochemical detection approaches. Two way analysis of variance (ANOVA) was implemented to quantify the main effects of laser irradiation, GO application as well as their interactive effects on all measured variables, and statistical comparisons were completed at the significance level of P < 0.05.The experimental results demonstrated that cumulative environmental light availability acted as the dominant environmental driver accounting for seasonal discrepancies in cucumber photosynthetic performance, yield formation and fruit quality. In spring, the cumulative sunshine duration reached 618.5 h; cucumber plants exhibited net photosynthetic rate ranging from 23 to 30 μmol/(m²·s¹), yield ranging from 6 300 to 6 900 kg per 667 m², and vitamin C content ranging from 6.97 to 9.23 mg per 100 g fresh weight. All these indicators were significantly higher than those measured in the autumn season with cumulative sunshine duration of merely 271.2 h. As an osmotic adjustment adaptive response triggered by low light stress, soluble sugar content in autumn harvested cucumber fruits was 2-3 times that of spring harvested fruits. Supplemental laser irradiation remarkably improved net photosynthetic capacity, facilitated fruit set and reduced fruit abscission, and consequently brought about stable yield increment in both spring and autumn seasons. Moreover, laser treatment simultaneously elevated the accumulation of soluble sugar and vitamin C in cucumber fruits. Root drenching with GO solution alone failed to produce statistically significant promotion on total cucumber yield across two seasons. Nevertheless, GO application persistently enhanced fruit soluble sugar content irrespective of seasonal light conditions. The regulatory influence of GO on vitamin C accumulation was season dependent and modulated by whether laser supplemental lighting was imposed, showing inconsistent performance between different growing seasons. Notably, the interactive responses to laser irradiation and GO root application displayed strong seasonal dependency. Under sufficient natural light conditions in spring, the combined treatment of laser plus GO did not generate prominent synergistic improvement on leaf photosynthetic traits and final yield. In contrast, under low light adversity in autumn, laser irradiation coupled with GO drenching exerted significant synergistic effects, which greatly boosted net photosynthetic rate and marketable yield. This combined treatment also enhanced fruit soluble sugar accumulation steadily in both spring and autumn growing seasons. According to comprehensive comparisons on photosynthetic physiology, yield performance and fruit quality, sole laser irradiation is recommended for spring greenhouse cucumber production for cost saving purposes, while the integrated regime of laser irradiation together with GO root drenching should be adopted to mitigate low light damages during autumn cultivation. This study provides solid theoretical foundation and practical technical references for the combined application of low cost light regulation and carbon based nanomaterials within protected horticultural systems.